"No!" Piper said. "Wait."

The wolves tilted their heads and studied the campers with huge golden eyes.

A heartbeat later, their masters appeared: a troop of hunters in white-and-gray winter camouflage, at least half a dozen. All of them carried bows, with quivers of glowing silver arrows on their backs.

Their faces were covered with parka hoods, but clearly they were all girls. One, a little taller than the rest, crouched in the firelight and s.n.a.t.c.hed up the arrow that had wounded Lycaon's hand.

"So close." She turned to her companions. "Phoebe, stay with me. Watch the entrance. The rest of you, follow Lycaon. We can't lose him now. I'll catch up with you."

The other hunters mumbled agreement and disappeared, heading after Lycaon's pack.

The girl in white turned toward them, her face still hidden in her parka hood. "We've been following that demon's trail for over a week. Is everyone all right? No one got bit?"

Jason stood frozen, staring at the girl. Piper realized something about her voice sounded familiar. It was hard to pin down, but the way she spoke, the way she formed her words, reminded her of Jason.

"You're her," Piper guessed. "You're Thalia."

The girl tensed. Piper was afraid she might draw her bow, but instead she pulled down her parka hood. Her hair was spiky black, with a silver tiara across her brow. Her face had a super-healthy glow to it, as if she were a little more than human, and her eyes were brilliant blue. She was the girl from Jason's photograph.

"Do I know you?" Thalia asked.

Piper took a breath. "This might be a shock, but-"

"Thalia." Jason stepped forward, his voice trembling. "I'm Jason, your brother."

LEO FIGURED HE HAD THE WORST LUCK in the group, and that was saying a lot. Why didn't he get to have the long-lost sister or the movie star dad who needed rescuing? All he got was a tool belt and a dragon that broke down halfway through the quest. Maybe it was the stupid curse of the Hephaestus cabin, but Leo didn't think so. His life had been unlucky way before he got to camp.

A thousand years from now, when this quest was being told around a campfire, he figured people would talk about brave Jason, beautiful Piper, and their sidekick Flaming Valdez, who accompanied them with a bag of magic screwdrivers and occasionally fixed tofu burgers.

If that wasn't bad enough, Leo fell in love with every girl he saw-as long as she was totally out of his league.

When he first saw Thalia, Leo immediately thought she was way too pretty to be Jason's sister. Then he thought he'd better not say that or he'd get in trouble. He liked her dark hair, her blue eyes, and her confident att.i.tude. She looked like the kind of girl who could stomp anybody on the ball court or the battlefield, and wouldn't give Leo the time of day-just Leo's type!

For a minute, Jason and Thalia faced each other, stunned. Then Thalia rushed forward and hugged him.

"My G.o.ds! She told me you were dead!" She gripped Jason's face and seemed to be examining everything about it. "Thank Artemis, it is you. That little scar on your lip-you tried to eat a stapler when you were two!"

Leo laughed. "Seriously?"

Hedge nodded like he approved of Jason's taste. "Staplers -excellent source of iron."

"W-wait," Jason stammered. "Who told you I was dead? What happened?"

At the cave entrance, one of the white wolves barked. Thalia looked back at the wolf and nodded, but she kept her hands on Jason's face, like she was afraid he might vanish. "My wolf is telling me I don't have much time, and she's right. But we have to talk. Let's sit."

Piper did better than that. She collapsed. She would've cracked her head on the cave floor if Hedge hadn't caught her.

Thalia rushed over. "What's wrong with her? Ah-never mind. I see. Hypothermia. Ankle." She frowned at the satyr. "Don't you know nature healing?"

Hedge scoffed. "Why do you think she looks this good? Can't you smell the Gatorade?"

Thalia looked at Leo for the first time, and of course it was an accusatory glare, like Why did you let the goat be a doctor? As if that was Leo's fault.

"You and the satyr," Thalia ordered, "take this girl to my friend at the entrance. Phoebe's an excellent healer."

"It's cold out there!" Hedge said. "I'll freeze my horns off."

But Leo knew when they weren't wanted. "Come on, Hedge. These two need time to talk."

"Humph. Fine," the satyr muttered. "Didn't even get to brain anybody."

Hedge carried Piper toward the entrance. Leo was about to follow when Jason called, "Actually, man, could you, um, stick around?"

Leo saw something in Jason's eyes he didn't expect: Jason was asking for support. He wanted somebody else there. He was scared.

Leo grinned. "Sticking around is my specialty."

Thalia didn't look too happy about it, but the three of them sat at the fire. For a few minutes, n.o.body spoke. Jason studied his sister like she was a scary device-one that might explode if handled incorrectly. Thalia seemed more at ease, as if she was used to stumbling across stranger things than long-lost relatives. But still she regarded Jason in a kind of amazed trance, maybe remembering a little two-year-old who tried to eat a stapler. Leo took a few pieces of copper wire out of his pockets and twisted them together.

Finally he couldn't stand the silence. "So ... the Hunters of Artemis. This whole 'not dating' thing-is that like always, or more of a seasonal thing, or what?"

Thalia stared at him as if he'd just evolved from pond sc.u.m. Yeah, he was definitely liking this girl.

Jason kicked him in the shin. "Don't mind Leo. He's just trying to break the ice. But, Thalia ... what happened to our family? Who told you I was dead?"

Thalia tugged at a silver bracelet on her wrist. In the firelight, in her winter camouflage, she almost looked like Khione the snow princess-just as cold and beautiful.

"Do you remember anything?" she asked.

Jason shook his head. "I woke up three days ago on a bus with Leo and Piper."

"Which wasn't our fault," Leo added hastily. "Hera stole his memories."

Thalia tensed. "Hera? How do you know that?"

Jason explained about their quest-the prophecy at camp, Hera getting imprisoned, the giant taking Piper's dad, and the winter solstice deadline. Leo chimed in to add the important stuff: how he'd fixed the bronze dragon, could throw fireb.a.l.l.s, and made excellent tacos.

Thalia was a good listener. Nothing seemed to surprise her-the monsters, the prophecies, the dead rising. But when Jason mentioned King Midas, she cursed in Ancient Greek.

"I knew we should've burned down his mansion," she said. "That man's a menace. But we were so intent on following Lycaon-Well, I'm glad you got away. So Hera's been ... what, hiding you all these years?"

"I don't know." Jason brought out the photo from his pocket. "She left me just enough memory to recognize your face."

Thalia looked at the picture, and her expression softened. "I'd forgotten about that. I left it in Cabin One, didn't I?"

Jason nodded. "I think Hera wanted for us to meet. When we landed here, at this cave ... I had a feeling it was important. Like I knew you were close by. Is that crazy?"

"Nah," Leo a.s.sured him. "We were absolutely destined to meet your hot sister."

Thalia ignored him. Probably she just didn't want to let on how much Leo impressed her.

"Jason," she said, "when you're dealing with the G.o.ds, nothing is too crazy. But you can't trust Hera, especially since we're children of Zeus. She hates all children of Zeus."

"But she said something about Zeus giving her my life as a peace offering. Does that make any sense?"

The color drained from Thalia's face. "Oh, G.o.ds. Mother wouldn't have ... You don't remember-No, of course you don't."

"What?" Jason asked.

Thalia's features seemed to grow older in the firelight, like her immortality wasn't working so well. "Jason ... I'm not sure how to say this. Our mom wasn't exactly stable. She caught Zeus's eye because she was a television actress, and she was beautiful, but she didn't handle the fame well. She drank, pulled stupid stunts. She was always in the tabloids. She could never get enough attention. Even before you were born, she and I argued all the time. She ... she knew Dad was Zeus, and I think that was too much for her to take. It was like the ultimate achievement for her to attract the lord of the sky, and she couldn't accept it when he left. The thing about the G.o.ds... well, they don't hang around."

Leo remembered his own mom, the way she'd a.s.sured him over and over that his dad would be back someday. But she'd never acted mad about it. She didn't seem to want Hephaestus for herself-only so Leo could know his father. She'd dealt with working a dead-end job, living in a tiny apartment, never having enough money-and she'd seemed fine with it. As long as she had Leo, she always said, life would be okay.

He watched Jason's face-looking more and more devastated as Thalia described their mom-and for once, Leo didn't feel jealous of his friend. Leo might have lost his mom. He might have had some hard times. But at least he remembered her. He found himself tapping out a Morse code message on his knee: Love you. He felt bad for Jason, not having memories like that-not having anything to fall back on.

"So ..." Jason didn't seem able to finish the question.

"Jason, you got friends," Leo told him. "Now you got a sister. You're not alone."

Thalia offered her hand, and Jason took it.

"When I was about seven," she said, "Zeus started visiting Mom again. I think he felt bad about wrecking her life, and he seemed-different somehow. A little older and sterner, more fatherly toward me. For a while, Mom improved. She loved having Zeus around, bringing her presents, causing the sky to rumble. She always wanted more attention. That's the year you were born. Mom ... well, I never got along with her, but you gave me a reason to hang around. You were so cute.

And I didn't trust Mom to look after you. Of course, Zeus eventually stopped coming by again. He probably couldn't stand Mom's demands anymore, always pestering him to let her visit Olympus, or to make her immortal or eternally beautiful. When he left for good, Mom got more and more unstable. That was about the time the monsters started attacking me. Mom blamed Hera. She claimed the G.o.ddess was coming after you too-that Hera had barely tolerated my birth, but two demiG.o.d children from the same family was too big an insult. Mom even said she hadn't wanted to name you Jason, but Zeus insisted, as a way to appease Hera because the G.o.ddess liked that name. I didn't know what to believe."

Leo fiddled with his copper wires. He felt like an intruder. He shouldn't be listening to this, but it also made him feel like he was getting to know Jason for the first time-like maybe being here now made up for those four months at Wilderness School, when Leo had just imagined they'd had a friendship.

"How did you guys get separated?" he asked.

Thalia squeezed her brother's hand. "If I'd known you were alive ... G.o.ds, things would've been so different. But when you were two, Mom packed us in the car for a family vacation. We drove up north, toward the wine country, to this park she wanted to show us. I remember thinking it was strange because Mom never took us anywhere, and she was acting super nervous. I was holding your hand, walking you toward this big building in the middle of the park, and ..." She took a shaky breath. "Mom told me to go back to the car and get the picnic basket. I didn't want to leave you alone with her, but it was only for a few minutes. When I came back ... Mom was kneeling on the stone steps, hugging herself and crying. She said-she said you were gone. She said Hera claimed you and you were as good as dead. I didn't know what she'd done. I was afraid she'd completely lost her mind. I ran all over the place looking for you, but you'd just vanished. She had to drag me away, kicking and screaming. For the next few days I was hysterical. I don't remember everything, but I called the police on Mom and they questioned her for a long time. Afterward, we fought. She told me I'd betrayed her, that I should support her, like she was the only one who mattered. Finally I couldn't stand it. Your disappearance was the last straw. I ran away from home, and I never went back, not even when Mom died a few years ago. I thought you were gone forever. I never told anyone about you-not even Annabeth or Luke, my two best friends. It was just too painful."

"Chiron knew." Jason's voice sounded far away. "When I got to camp, he took one look at me and said, 'You should be dead.'"

"That doesn't make sense," Thalia insisted. "I never told him."

"Hey," Leo said. "Important thing is you've got each other now, right? You two are lucky."

Thalia nodded. "Leo's right. Look at you. You're my age. You've grown up."

"But where have I been?" Jason said. "How could I be missing all that time? And the Roman stuff ..."

Thalia frowned. "The Roman stuff?"

"Your brother speaks Latin," Leo said. "He calls G.o.ds by their Roman names, and he's got tattoos." Leo pointed out the marks on Jason's arm. Then he gave Thalia the rundown about the other weird stuff that had happened: Boreas turning into Aquilon, Lycaon calling Jason a "child of Rome," and the wolves backing off when Jason spoke Latin to them.

Thalia plucked her bowstring. "Latin. Zeus sometimes spoke Latin, the second time he stayed with Mom. Like I said, he seemed different, more formal."

"You think he was in his Roman aspect?" Jason asked. "And that's why I think of myself as a child of Jupiter?"

"Possibly," Thalia said. "I've never heard of something like that happening, but it might explain why you think in Roman terms, why you can speak Latin rather than Ancient Greek. That would make you unique. Still, it doesn't explain how you've survived without Camp Half-Blood. A child of Zeus, or Jupiter, or whatever you want to call him-you would've been hounded by monsters. If you were on your own, you should've died years ago. I know I wouldn't have been able to survive without friends. You would've needed training, a safe haven-"

"He wasn't alone," Leo blurted out. "We've heard about others like him."

Thalia looked at him strangely. "What do you mean?"

Leo told her about the slashed-up purple shirt in Medea's department store, and the story the Cyclopes told about the child of Mercury who spoke Latin.

"Isn't there anywhere else for demiG.o.ds?" Leo asked. "I mean besides Camp Half-Blood? Maybe some crazy Latin teacher has been abducting children of the G.o.ds or something, making them think like Romans."

As soon as he said it, Leo realized how stupid the idea sounded. Thalia's dazzling blue eyes studied him intently, making him feel like a suspect in a lineup.

"I've been all over the country," Thalia mused. "I've never seen evidence of a crazy Latin teacher, or demiG.o.ds in purple shirts. Still ..." Her voice trailed off, like she'd just had a troubling thought.

"What?" Jason asked.

Thalia shook her head. "I'll have to talk to the G.o.ddess. Maybe Artemis will guide us."

"She's still talking to you?" Jason asked. "Most of the G.o.ds have gone silent."

"Artemis follows her own rules," Thalia said. "She has to be careful not to let Zeus know, but she thinks Zeus is being ridiculous closing Olympus. She's the one who set us on the trail of Lycaon. She said we'd find a lead to a missing friend of ours."

"Percy Jackson," Leo guessed. "The guy Annabeth is looking for."

Thalia nodded, her face full of concern.

Leo wondered if anyone had ever looked that worried all the times he'd disappeared. He kind of doubted it.

"So what would Lycaon have to do with it?" Leo asked. "And how does it connect to us?"

"We need to find out soon," Thalia admitted. "If your deadline is tomorrow, we're wasting time. Aeolus could tell you-"

The white wolf appeared again at the doorway and yipped insistently.

"I have to get moving." Thalia stood. "Otherwise I'll lose the other Hunters' trail. First, though, I'll take you to Aeolus's palace."

"If you can't, it's okay," Jason said, though he sounded kind of distressed.

"Oh, please." Thalia smiled and helped him up. "I haven't had a brother in years. I think I can stand a few minutes with you before you get annoying. Now, let's go!"

WHEN LEO SAW HOW WELL PIPER AND HEDGE were being treated, he was thoroughly offended.

He'd imagined them freezing their hindquarters off in the snow, but the Hunter Phoebe had set up this silver tent pavilion thing right outside the cave. How she'd done it so fast, Leo had no idea, but inside was a kerosene heater keeping them toasty warm and a bunch of comfy throw pillows. Piper looked back to normal, decked out in a new parka, gloves, and camo pants like a Hunter. She and Hedge and Phoebe were kicking back, drinking hot chocolate.

"Oh, no way," Leo said. "We've been sitting in a cave and you get the luxury tent? Somebody give me hypothermia. I want hot chocolate and a parka!"

Phoebe sniffed. "Boys," she said, like it was the worst insult she could think of.

"It's all right, Phoebe," Thalia said. "They'll need extra coats. And I think we can spare some chocolate."