After school, the student council members were gathering in the student council room.

Starting with the student council president Zelcyone, there was vice president Clayda, secretary Elma, treasurer Lunorlla, and general affairs Ramza.

Although, the positions other than student council president were just for convenience, in practice the student council president Zelcyone managed everything by herself.

At the door, there was a sign that showed meeting in progress and prohibition to enter, so there wasn't any daredevil that dared to even knock. The door was locked and the window was covered with curtain. Of course, the confirmation that there was no hidden camera or listening device set up inside had been finished. It was only this room that even the command headquarter couldn't interfere with.

「Then, let's begin today's agenda right away.」

Zelcyone got the ball rolling with that. And then at the same time, a window started up in front of the four. A picture of a girl and the t.i.tle of this meeting were displayed in the window.

『Grace Nurture Plan』

That was to say, it was a plan of in what way to nurture Grace to become a flawless student council president with one hundred percent approval rating.

The student council members, nicknamed 『Quartum』 with Clayda as the first were tilting their head inside their heart even though it didn't show on their face. Why was the student council president favoring Grace until that much? It was completely a puzzle for the four.

Zelcyone looked over all of them and continued her talk.

「The AU collision the other day, there were multiple Entrances appearing contrary to the prediction, and then there was the appearance of magic weapon that was unforeseen. We almost received a grave damage.」

Clayda raised her hand.

「Ah, does the lab learned something from that?」

「No, the cause is unknown. I was also showed the lab data and a.n.a.lysis result from the headmaster but……certainly there were a lot of baffling points. But, we were able to understand that there wasn't any miss committed by the observation team or even that the prediction was half-baked. Perhaps there is some kind of rule that we aren't aware of……perhaps, there is even the unseen hand of G.o.d at work……」

Elma put her hand on her cheek and made an anxious expression.

「Is that so……it's a bit eerie isn't it?」

「Well, but, if it's something that cannot be understood even after thinking then it can't be helped.」

Ramza said brightly. Lunorlla stared at Zelcyone hesitantly.

「But……what is the relation of that with Grace?」

Zelcyone folded her arms and stared at empty air with a grim face.

「With the appearance of unpredictable Entrances, it cause anxiety in people's heart. A hero is needed exactly at this time. That kind of person is exactly the person that is worthy to be the next student council president. But──」

Zelcyone tapped on the desk with her finger and one more window started up. Clayda frowned when she saw the girl that was projected there.

「This is, cla.s.s president of second year first group Hyakurath?」

「There is no other rival candidate for Grace other than this Hyakurath isn't it?」

「Is Aine-san not a rival candidate?」

「Aine is……curiously she feel unrelated with this kind of political world. She ought to be a purer existence don't you think so?」

The four nodded at Zelcyone's words──but, honestly they completely didn't understand what she was talking about.

「Let's continue the topic. This Haykurath, it seems she finally carried out Heart Hybrid with Kizuna the other day.」

Clayda reflexively stood up.

「Seriously!?」

This was a scoop. The four began to calculate in their heart how much they could sell this information to the newspaper club. Zelcyone spoke seriously without even feeling concerned of what was going on inside the four's mind.

「I thought that with how she couldn't do Heart Hybrid, she wouldn't be a threat against Grace……but like this it's a different story. An even more power up has to be prompted for Grace no matter what.」

Ramza tilted her head.

「About that, how are we going to do that?」

Zelcyone wrapped her fingers together and grinned.

「I properly thought of an idea. We are carrying out the strategy right away.」

The four were a.s.saulted with a bad premonition at the same time.

'Aah, this is, going to be something bad.' They thought.

A mail from student council reached Kizuna's information terminal.

『Show yourself in student council room after school.』

「There is no mention about the matter or anything here……just what business will it be?」

Kizuna knocked on the student council room's door while harboring a tinge of unease.

「Enter.」

Zelcyone's voice replied from inside.

「Excuse──me……?」

The familiar student council president. However inside was completely empty. There was no one.

'This is strange huh? There is certainly a reply just now.' Kizuna stepped inside the student council room while thinking so.

At that moment, a strange sensation attacked Kizuna.

「!? This is-!?」

A moment of dizziness, and then the sensation of electrical signal rus.h.i.+ng around inside his body. The scenery of student council room vanished and changed into a very ordinary living room.

「Love Room? How……」

However there wasn't anyone replying to him.

「Strange……even though here is undoubtedly student council room……since when I entered Love Room?」

It was a bright room with white wall. The window was large and outside a garden could be seen even if it was small. Inside the room was a living room set of a television with sofa around it and a table. There were necessary electrical appliances for daily life at the dining kitchen like refrigerator and microwave oven. And then the shelves were crammed with tableware like plates and cups and so on. And then there was a table for having meal with four chairs prepared.

It was a s.p.a.ce that was overflowing with lived-in feel.

「The atmosphere is really normal like a common home huh……why is this kind of environment data is used?」

But before thinking about that, the more pressing problem was who was the one that called Kizuna into the Love Room and what was their objective.

「Hm?」

He could hear a sound.

「The bathroom?」

He could hear a faint water sound. Kizuna carefully opened the door of the changing room. Someone was at the other side of the frosted gla.s.s. He could see blurred sking color moving.

Just who in the world?

At that time the shower sound stopped and the door of frosted gla.s.s opened.

「He……」

「Wha……」

Grace holding a towel in her hand was standing there with a puzzled face. Drops of hot water were glistening on her body. Compared to the other girls in the cla.s.s her figure was small, slender, and delicate. The size of her b.r.e.a.s.t.s were also a size smaller supposedly, but they looked splendid on her small stature. Besides, they were depicting a very pretty shape.

「Ni, Nii-sama……wha, wha」

This wasn't the time for him to appreciate the sight leisurely like this. Gazing thoroughly at the body of a little sister was just──,

「Eh? Little sister……」

「NII-SAMA YOU IDIOTTTTTTTT-! GET OUT QUICKLYYY────!!」

「SO-! SORRY GRACE!」

Kizuna returned to the living room in panic. He threw himself on the sofa and sat down and then he covered his eyes with his hand. The naked little sister that he saw just a moment ago was burned at the back of his eyelid. When he closed his eyes, the fresh figure was revived in his mind and his throbbing heart couldn't settle down at all.

Loud footsteps *dozu dozu* resounded and Grace with her body wrapped in bath towel arrived. As though to appeal that she was pretty angry, she puffed up her cheeks with a glare at Kizuna.

「Geez! Nii-sama you idiot-! Doing something that look like peeking like that is wrong!」

「You, you're wrong! That was an accident!」

「I, it's not like I hate it but……that, there is my preparation of heart……」

「Hm? I cannot really hear that.」

「Geez-, I don't care anymore!」

She quickly turned her back on him and ran through the corridor with loud footsteps.

「Zelcyone-sama…..this is?」

Clayda directed to Zelcyone a face that begged for explanation.

Zelcyone and the Quartum were standing on the rooftop of the school building, staring at the figure of Kizuna and Grace that were projected in a floating window. That video was the video of the Love Room's internal that was currently placed before their eyes.

「Fufu……right now those two were under the impression they are real brother and sister.」

When Kizuna was on the way of heading to the student council room, Zelcyone's 『Heart Rebuild』 planted a suggestion in him. The place where he arrived that he thought as the student council room was actually the rooftop, and the room that he entered was the Love Room.

The four people of Quartum yesterday secretly borrowed Love Room from Nayuta Lab by making use of the cover of the night. They were only secretly borrowing it, by no means that it was stealing, that was the official point of view of the student council side.

「It's obvious that there is difference in Heart Hybrid's effect depending on the situation. Setting the situation and Heart Hybrid procedure to match one's taste mean everything. It can be thought like that.」

「Well, is that actually wrong?」

「No, it's correct. But, there is a blind spot in the method until now.」

「Wha, what is it……?」

The four Quartum gulped.

「The blind spot is that it was only the female side's taste that was used as the focus, while the other side, that is Kizuna, his taste, excitement, and sense of immorality weren't considered at all!」

「「「「!? AaAAAH! I, INDEED-!!」」」」

The four made a shocked expression.

「There I planted suggestion into the two. The false setting that they are actual brother and sister. Right now those two are inside a world where they are a common brother and sister of a very normal family. With the normal Heart Hybrid, they won't be able to get out of the territory of it being a mission. Especially Kizuna. But, this time what attacked that guy is the real excitement and nervousness, and then desire and sense of immorality. I don't understand that guy's actual taste, but there a beautiful girl like Grace becomes his little sister, what's more he have a relations.h.i.+p with her. There is no way he won't get excited.」

Ramza yelled excitedly.

「As expected from Zel-sama!」

「To think so deeply……until that far……」

「How marvelous! Zelcyone-sama!」

「That's really amazing! Zel-sama!」

Zelcyone didn't feel that bad getting praised by her subordinates. Her cheeks unconsciously loosened.

「Now now, it's nothing big. Stop praising me with just that.」

After that she turned off the monitor switch.

「Eh? Is it fine to not look out at the situation?」

Clayda tilted her head.

「Fuh, it will be fine even if we don't do anything boorish like peeking. From here on it those two's problem. We will wait for the result here.」

Clayda clapped her hands *pan* and gave instruction to her comrades.

「Yoosh, then we are going to wait here. If I remember right there are table and chairs used for event at the equipment room. Let's bring those here. Also, someone go buy drinks.」

「Aa─, I'll do that. Is there any request?」

「Then, I'll go buy snacks at the canteen!」

Turning her back toward the lively commotion of the Quartum, Zelcyone was staring at the Love Room.

「I'm counting on you……Kizuna.」

When Kizuna returned to his own room, he sat down on the chair of his study table. He put his weigh on the chair's back and bended his body.

「……Guess I'll study.」

Thinking that, he tried to open his text book and reference book, but what flickered in front of his eyes were only his little sister's nakedness.

「Aaah, s.h.i.+t. My mind is distracted and cannot concentrate at anything!」

──'She must be angry huh……I'll go apologize right away.'

He stood up from the chair and went out to the corridor. Grace's room was beside his, so he arrived in front of her door right away. But, what should he say to her?

Kizuna kept standing at the corridor and got lost in his thought. But, at that time, he could faintly hear a voice from Grace's room.

──'Grace?'

He slowly put his ear on the door without making sound.

「Nn……fuh…ahn……yah, aaan♥」

Grace's voice that sounded like she was stifling her pleasure. Kizuna's spine s.h.i.+vered from a chill.

──'Do, don't tell me……Grace?'

Inside the room Grace was comforting her body with her own hand.

She was groping her left breast with her right hand, while her left hand slipped between her crotch. At first she only touched the places slightly, but perhaps from the sense of security that there was no one and no one could see her, her hands movement were gradually getting bolder.

「Kuh……aa, nn……yah……aa」

However, only her voice that she had to stifle no matter what. Her big brother was next door. Making a loud voice would expose what she was doing.

However the moment her hand pecked at a pleasant place that even she herself didn't know, her voice abruptly leaked out.

「Aaah♥ Ni, Nii-sama……don't, not there-♥」

Kizuna who was outside the door spontaneously thought that his heart was going to stop.

For a moment he thought that he got found out how he was listening in. However, that wasn't it.

──'Grace, you……are imagining me……?'

He swallowed those words that he himself couldn't understand the meaning along with his saliva. And then when he chewed on the meaning of those words, Kizuna's heart beat was beating loudly. It made his head feverishly hazy.

'Impossible……did I mishear?'

Not knowing about that agitation of Kizuna, Grace became absorbed in her own activity and her voice was getting louder while she was unaware.

「Fuah, Ni, Nii-sama♥ is, watching, me……aAAN! I, if Nii-sama do it like that-, a, noo……AaAANN♥」

Kizuna felt like a lewd watery sound was mixed somewhat through her voice. And then, finally the voice of Grace who was overcame by emotion slipped through as though to caress Kizuna's ears.

「A, a, aaa♥ AAAAANNNNN♥ YAAAANNN♥♥」

──'Grace-.'

Kizuna was also unable to contain the excitement of himself that became big and hard.

As though to escape from Grace's rough breathing that he could hear from across his shoulder, he moved his feet sneakily and returned to his room.

He collapsed on the bed and tried to calm down his chaotic mind. But, it was just a pointless endeavor. After encountering that kind of shocking scene, there was no way he would be able to be calm.

Even now his heart was beating hard, his lower body was also pus.h.i.+ng up at his trouser.

「Grace……」

Even though there was a single door between them, but mysteriously it felt like he had seen Grace's masturbation directly, the image was vividly resurrected in his brain.

She caressed her own breast and then her fingers twisted the pink tip that became hard from the stimulation. So that it would be fair to the other breast that was lonely, her hand would be affectionate to it with a gentle rolling. And then her other hand was squirming bewitchingly between her legs. Faint water sound resounded from the bush that had the same color with Grace's hair. In the valley deeper inside, the secret spot that still hadn't been seen by anyone yet──,

His information terminal vibrated.

Kizuna spontaneously sprang up and confirmed at the screen.

『Nii-sama, sorry about just now. I also spoke too far. There is a bit of my homework that I don't understand, so won't you teach me?』

He let out a sigh of relieve that felt like strength left from his whole body.

For a moment it felt like he was seen through how he was having dirty delusion, but there was no way that could be true. How he was eavesdropping shouldn't be found out, and he would also not reveal anything about that from his mouth. Kizuna swore that to himself and he visited the room of his little sister with his usual big brother face.

Grace was wearing a T-s.h.i.+rt with wide neckline and a large size where it almost slipped off from her shoulder. Her lower wear was a short skirt that spread in flare shape and bare feet.

And then he watched over her study like usual. He stood beside Grace's study table and looked down on her hand from above. It looked like she was solving homework problems without any difficulty.

「Grace is smarter than me. Perhaps soon it will be you who is teaching me.」

Grace chuckled.

「If that happen then I'll teach Nii-sama attentively with great care.」

「Attentively……」

Grace's face went red with a puff and she waved her hand in panic.

「It, it's a metaphor! It's just a metaphor! I, I won't actually cling, or glued myself at Nii-sama──」

「I, I get it, I get it. Rather than that, let's continue.」

「Uu……」

Grace faced her desk once more, but at that time the exposed chest of Grace entered his eyes.

It was a s.h.i.+rt with largely opened neckline, furthermore because the size was largish for Grace, her chest could be seen completely from the gap. What's more it wasn't just the white skin that showed the trace of roundness that he could see, but even until the pink colored part at the tip.

「Hm? What's the matter, Nii-sama?」

「Eh! N, no……that」

Kizuna was lost of how to reply, but if he gave strange excuse only to get found out later then he might get despised. Kizuna honestly told the truth.

「I can see your chest……」

Grace looked down and when she confirmed the sight, her face reddened and she hugged her chest in panic.

「That……my bad. I didn't do it in purpose but……sorry, for some reason today this keep happening.」

Grace fell silent for a while, but before long she replied with voice so small that sounded like mosquito buzzing.

「It's not, really a big deal……I was also seen just now……besides, it's fine even if Nii-sama see it. If it's Nii-sama then」

「I, is, that so?」

With a bright red face, Grace nodded while keeping silent. And then, she unfolded her arms and intentionally opened the large neckline, so that it was easier for Kizuna to see.

His little sister's lovely breast flew into Kizuna's sight once more. He unconsciously gulped. Perhaps even Grace could hear his gulp.

As though waiting for something, Grace kept staying unmoving. Her skin was dyed bright red until her ears.

There was the sound of heart beating so noisily. It was unknown whether it was the sound of Kizuna's heart, or Grace's heart.

Kizuna slowly reached his hand toward Grace as though to embrace her.

If, she looked like she was against it even just for a bit, then he would draw back his hand. He persuaded himself like that and he inserted his hand through the opened neckline. Even when his hand grazed Grace's smooth skin, she didn't move.

And then Kizuna's hand finally touched Grace's chest gently.

「Aa……♥」

Sigh of joy leaked out from Grace's mouth.

It was the voice that he heard from beyond the door just now.

「Grace……」

He was only calling her name, he wasn't particularly making any specific question. However Grace nodded to express her affirmation.

「Yes……nii-sama.」

Kizuna put strength into his hand and thoroughly rubbed as though to ascertain the sensation of his little sister's breast. Grace's body trembled and she lifted her chin. Her eyebrows crumpled and she showed to Kizuna the face of a woman that was tormented by pleasure.

「Haa……aan♥」

A sweet sigh was played from her moist lips. The tip of Grace's breast became hard and pointed inside Kizuna's hand. That sensation felt good on his palm and wanting to taste that pleasure many times, his hand continued to rub by itself continuously.

「Ah, haaaaahn, ah, a, aaaah」

Kizuna moved his hand inside Grace's clothes and his groping found out the other hill.

「Nnh♥ A, ya……yaaannn♥」

Grace twisted her body and wriggled her waist restlessly. However, it was clear that she wasn't hating it. Kizuna firmly rubbed the breast of that side too so it would get bigger like the other side.

「Ni, Nii-samaa……like that, only, my breast……」

It sounded like a demand for him to do more kind of things. He didn't understand what Grace herself was thinking, but she didn't try to stop him.

「……ah」

When Kizuna pulled out his hand from the neckline, Grace looked up at Kizuna with an eyes like an abandoned puppy.

「Grace, stand up.」

Kizuna lent his hand to the staggering Grace and made her stood to face him. They had never stared at each other thoroughly from so close distance like this. Kizuna was made to notice once more how beautiful the molding of his little sister's face that he wanted to sigh in admiration.

His own face was being reflected on those red eyes that were moist with tear.

The lips of the brother and sister who were staring at each other were drawing near naturally.

「Nn……」

Their lips touched and slowly pushed. A luscious texture spread from the lips. Kizuna thought that there was still parts that he hadn't known yet from his little sister that he was close with. When he thought that after this he would be disclosing those secret parts, his feeling swelled up whether he wanted or not.

His hand circled around Grace's waist and he pressed his waist closer to convey to her his excitement. Grace didn't react, but surely she noticed. Kizuna used his hand to gently caressed Grace's b.u.t.t. From that, Grace's body reacted with a twitch.

Their lips separated and Kizuna talked with the nearness that was impossible in normal everyday life.

「Does it, feel good?」

Grace returned a smile that was a mix of shyness and happiness.

「It feels good……I didn't, know……that it feels this good, to be touched by other.」

Kizuna felt like those words encouraged him.

「……Grace.」

Kizuna flipped the fringe of Grace's T-s.h.i.+rt. Guessing his intention, Grace raised both her hands and helped her big brother to take off her clothes.

She looked like a child who got her parent help to take off her clothes. When the s.h.i.+rt was taken off from Grace's both arms that were in banzai pose, there was nothing else that was hiding her upper body. Although they were inside the room, but it was really a defenseless figure.

'Wasn't she planning to tempt me right from the start?' Such thinking crossed his mind. Kizuna put his hand that felt like it would tremble from nervousness to her skirt, and then he pulled it down too.

A dazzling white underwear was covering Grace's important spot. It had a clean and neat impression, yet a lot of frills were used on it that it embodied lovely s.e.xiness.

When his hand was going to touch at that underwear too, Grace spoke timidly.

「Err……Nii-sama too, that」

She must be wanting to appeal that it was embarra.s.sing that it was only her who was naked. Kizuna took off his s.h.i.+rt too, and then he easily took off the T-s.h.i.+rt that he wore as underwear replacement, and threw it to the floor. When he lowered his trouser, he became equal with Grace.

He gently hugged his little sister's shoulder, and after embracing and kissing her one more time, he led her to the bed.

Both of them lied down side by side with their body pressing against each other. It was a single bed, so naturally they would fall if their body didn't press against each other. When he let Grace to use his arm as a pillow, she happily rubbed her cheek on him. When he caressed her pink hair, her eyes squinted from pleasant feeling.

「For some reason, it feels like my dream is coming true a bit.」

「Dream?」

「My dream for the future, is to be Nii-sama's wife.」

Kizuna kissed her forehead hearing that cute dream.

Grace touched at Kizuna's ear, mouth, Adam's apple, and chest as though she was tampering with rare thing. And then her hand stopped after tracing his abs.

「Eh? Grace. You are stopping there?」

When he said that teasingly, Grace frowned and made a pouting expression 'muu─' testily.

「For Nii-sama who said meany thing like that, I'll do this!」

Grace grasped that from above Kizuna's underwear with all her strength.

「tsu……!?」

Grace's cheeks stiffened with convulsion.

「It……it's this, hard……」

She stared at what she was grasping with a glance.

「……Want to try, touching it directly?」

'Eeeh!?' Grace directed that kind of face to Kizuna. As expected it seemed she didn't have the determination to go that far. Kizuna touched Grace's breast.

「Kyaahn!♥」

When he rubbed up her whle breast while pressing hard on the stiff tip, she began to raise a sweet voice at once.

「Uh, aaa……Ni, NIi-samaa♥」

「Here, Grace too.」

「Uu……」

Grace became teary while her hand slipped inside Kizuna's underwear. And then the moment she touched Kizuna, she twitched and her shoulders trembled. Perhaps her feeling was like someone who was scared of snake jumping out from the bush. However Grace squeezed out her courage and caressed as though to soothe that gooseneck. When she grew used to it, her way of touching was gradually growing bolder. She was starting to caress the whole shape of Kizuna's thing as though to ascertain the shape.

「It has……this kind of shape……besides, it's this hard……this hot……it's always in this kind of state……」

「It's not always like this you know? It's only when I'm excited.」

Grace's face turned bright in a flash.

「The, then Nii-sama is, getting excited because of me?」

In exchange of a reply, Kizuna slid his hand toward Grace's lower abdomen and touched her important place from above her underwear.

「Fuaaan! ♥Ni-, Nii-sama, that place-!」

Kizuna's fingertips became moistly wet. It seemed that Grace was also really excited.

「Even though your place here is this drenched, you cannot speak so cheekily.」

When Kizuna spoke jokingly, Grace tilted her head seemingly unable to understand his meaning right away. But the next moment, she pulled out her hand in panic from Kizuna's underwear, then she hid her own crotch with both hands.

「Wha……it's, it's like this」

She must be feeling surprised herself. She was staring at the fingertips that were touching her underwear with a surprised look. Her fingertips were s.h.i.+ning glisteningly with sticky liquid.

「You will catch cold wearing that. Onii-chan will take it off.」

Grace was startled and she lifted up her body.

「No, no need. I will take it off myself.」

Rather than the shyness from being naked, her shyness of having her drenched underwear taken away outweighed it. Grace took off her underwear resolutely then tossed it under her bed.

「No, now, it's unfair if it's just me. Nii-sama too, take it off!」

She folded her arms angrily to hide her embarra.s.sment.

Kizuna took off his underwear with a wry smile. During that time, he felt Grace's gaze piercing him.

When they sat on the bed facing each other, Grace stared at Kizuna's eyes. But, perhaps she was really curious because her gaze was stealing glances at below. She looked lovely.

「Are you curious?」

「Wha, what is Nii-sama talking about!?」

She averted her face in panic. However, she became resigned soon and asked him with an upward gaze.

「……It's obvious I'll be curious right? It's the thing……of the person I like.」

「Me too. Grace, come here.」

Grace sighed in relieve. She approached Kizuna happily, her back bended and she peered at Kizuna's thing. And then, she gingerly reached out her hand and began to stroke it.

「It has a curious sensation……this lower thing too.」

Grace's palm was tasting the sensation of something that was inserted into a bag. It was also the first time for Kizuna to feel the soft sensation of Grace's hand.

「Ah……Nii-sama, something is coming out from the tip.」

Grace scooped the drop that was oozing out from the tip and stretched it between her fingers.

「That's, the proof that I'm excited by Grace. Because you touch me, I get excessively excited.」

Grace's mood improved.

「I see, is that so! Fufu, it's the same like my place there.」

Perhaps getting carried away, she tampered with Kizuna's thing with a bold hand movement and created feeling of pleasure. At this rate, it felt like he would cross his limit in the blink of eye.

「Grace, I too……」

His hand reached out toward Grace's crotch, but Grace quickly changed the direction she faced and ran away from his hand.

「Nn?」

「Ri, right now, that's……no good. Surely, it will be terrible in various things.」

'Hahaa, I see'. With that Kizuna recalled of the underwear that she hid under the bed just now. Right now that place must be overflowing with honey to the degree that she was aware of it without even looking.

「Then, I have to check it no matter what! As a big brother!」

「Uoo!? Wha, what are you doing! Nii-sama!?」

Kizuna lifted up Grace's body in his arms and changed the direction of her face, and pinned her down in a flash. For an instant he felt that the hand-to-hand fighting skill cla.s.s didn't go to waste. Even Kizuna never even imagined that it would be used for something like this.

Kizuna moved above Grace and before his eyes there was the secret place that Grace was desperately hiding.

「This is……certainly」

He understood why she wanted to hide it. The red bush was also damply wet with dew, the inside of her thighs was glistening stickily with wetness. The valley where that honey was welling up from was getting so hot it felt like steam would come out.

「Aah……geez, stupid Nii-samaaa……」

She said her resentment with tearful voice, but Kizuna was fixed on Grace's important place. He slowly opened the chasm with his fingers.

「Hiah! ♥♥ Aa♥ Don't, there♥」

He blew out his breath 'fuh'.

「Hih!」

And then at last his parted that chasm with his fingers. It made *kuchuri* sound a thread was formed from the honey.

「If the little sister just stay silent and made to feel good by the big brother──!?」

Suddenly a pleasure ran through Kizuna's crotch.

「Hm, hmph……for Nii-sama of all people, to expose this vital spot before my eyes……」

Grace grasped Kizuna with her slender fingers and began to stroke up and down. And then her other hand caught the shaking bag and gently ma.s.saged it with her palm.

「Kuuh! Gra, Grace! Wa, wait!」

「I won't wait! If, if I wait, I'll immediately co-……」

「Eh?」

「Shu, shut up! Someone like Nii-sama, can just finish up by your little sister's hand!」

Pleasure stabbed through Kizuna's body from his crotch.

「Kuh……!」

He gritted his teeth and endured. If he let his guard down now, he would sprayed out his desire on his little sister's face.

However, by a bit of trial and error, Grace immediately learned what to do to make Kizuna felt even better.

Kizuna also didn't want to lose.

He opened Grace's chasm and his fingertip shallowly crawled in.

「Hyaaaah! ♥♥ A, aa, tha, that's, cheating♥」

Kizuna too, in order to search for the spot where Grace felt it the most, his finger traced her inside wall. Grace's body were repeatedly convulsing twitchingly. Her velvety skin sweated and stuck on Kizuna's skin further. The two became even more drunk with the sensation of their body becoming one.

「Uh!」

Kizuna's genital was enveloped in intense heat.

「Do, don't tell me……Grace──uwah!」

Using the opening when he was careless, their body position was reversed. This time it was Grace's turn to pin down Kizuna.

「This sis mhy whin. Jhust chome lhike this.」

He was able to understand what she was saying. But, then, to say nothing of face, he would release himself inside his little sister's mouth. The l.u.s.t that he spurted out wouldn't come out to open air but got drunk directly by his little sister.

From his tailbone, l.u.s.t that was smeared in immorality ran through as s.h.i.+ver.

To escape from that l.u.s.t, Kizuna sucked at Grace's gus.h.i.+ng spring.

「NYaaaaaaaaaaaah♥♥ A, aahhiuh, hih, hyuun!♥♥」

Grace's mouth spontaneously let go of Kizuna and she shrieked. Kizuna licked Grace's honey noisily. The taste was a mysterious flavor that he never tasted until now, it was sweet, refres.h.i.+ng, and made his heart felt at ease.

──'Delicious.'

Kizuna became absorbed in licking that sacred chasm and he continued to suck. He also used to put the protuberance that became bigger compared to just now between his lips and licked it with his tongue.

「♥♥♥!! Tsu……! ♥……nnnh! ♥♥」

Grace's body shook and a lot of honey gushed out from her chasm.

「Ni, Nii-sama……hamu……nhii-hyama」

Grace sucked at Kizuna's thing once more. She moved her tongue inside her mouth and sucked strongly at the same time.

Only instinct and affection stirred up the two. And then, beautiful radiance of magic power began to envelop the two. Heart shaped light emerged inside Grace's eyes.

When it was only a step more until the climax, both of them laid their hands to each other at the same time.

──And then,

Both of them arrived at the peak simultaneously without even any deviation of a single millisecond.

「!? Nnnnh♥♥♥……♥♥♥……!!♥♥♥ Nh♥ Nh♥ Nh♥♥♥♥♥」

Grace's secret sprin spouted out sweet honey with especially rich fragrance like a geyser. Kizuna was drinking it without letting go of even a single drop.

And then Grace too, her throat gulped down the life energy Kizuna released and sent it into her womb interior. For Grace, it was something that more delicious than anything, it warmed her body and filled her empty part.

The magic power that was created from the two was filling in the other's body, recovering their magic power, and created new power.

The Heart Hybrid succeeded and that magic power rushed through their body. That light also washed away Zelcyone's suggestion at the same time.

Grace rolled down from above Kizuna and lied down on the bed. And then, as though remembering something, she lifted her body and stared at Kizuna.

「E……h? Nii, sama……?」

Kizuna too, he stared at Grace with similar expression.

「Grace……this is」

Grace noticed with 'hah' and her face scowled.

「This is surely Zel's doing. That fellow……just what is she planning?」

When he was told that, Kizuna also recalled something. Surely, a hypnotism or something was applied on him while he was heading to the student council room.

「But──」

Grace's cheeks reddened and her mouth turned down at the corners.

「Well──it wasn't, a bad dream.」

Kizuna spontaneously smile.

「……You're right.」

Grace drew close to Kizuna, then she leaped on his chest.

「O, Grace?」

「This is a rare chance. Just for a bit more……I want to be real siblings.」

「Real siblings won't……must not do something like this though.」

After replying so with a wry smile, he embraced Grace's body.