"Look who it is," he said. "The cheating skeleton and his girl sidekick. Why am I even here?"

"You're here because you have a choice," Skulduggery said. "Hammer Lane is closing down so you're being sent to a new prison. If you co-operate, you can go to the gaol at Keel, maybe Funshog. If not, you can go to The Depths."

A flicker of something on Nadir's face. "You wouldn't send me there. You couldn't. I've killed a few people, yeah, but I haven't... You can't just send someone to..."

"We can," Skulduggery said, "and we will. Unless you co-operate."

"Co-operate how?"

"Undo what you did to Valkyrie."

Nadir looked at him, then at Valkyrie. "What?"

"Undo it," Skulduggery said.

"Undo what?"

"You're not doing yourself any favours."

"Listen, I have no idea what you want me to do, or undo. Tell me what it is, and I'll do it."

"You shunted me," Valkyrie said.

He made a face. "I did not."

Skulduggery got to his feet. "Let's go."

"Wait!" Nadir said. "Just hold on a second. Tell me what you think I did."

Skulduggery stayed standing, but didn't move. "You performed some kind of delayed shunt on Valkyrie when you attacked her at Hammer Lane."

"I don't know what you're-"

Skulduggery took a step towards the door.

"OK!" Nadir cried. "OK, fine, you say I attacked her, then I attacked her. I don't remember doing it, but I'd just been unhooked from that machine so, yeah, OK, maybe I did."

Valkyrie asked, "What exactly did you do? My arm hurt for a few days and then suddenly I was in another dimension. Twenty minutes later, I was back here."

Nadir sat forward, his eyes suddenly excited. "What was it like? It had a breathable atmosphere obviously, but what else did it have? Were there animals? Were there people?"

"You've never been there yourself?"

"No," he said. "God, no. Finding a frequency for a new dimension is one thing, but actually travelling there? What if the air is toxic? What if I appear in the middle of a volcano? What if there is no planet to stand on? There's a reason why there aren't many Dimensional Shunters still around, you know. Most of them are nothing but dust in some weird reality where the laws of physics are backwards. But the dimension I sent you to it's habitable. This is amazing. Do you know how rare that is? I found a previously undiscovered reality."

"And you sent me there," Valkyrie said. "How?"

Nadir nodded. "Right, yeah. It's called echoing. It's when a shunt doesn't work right away. Instead of one great big shunt, you get a kind of echo of a shunt. It echoes and echoes and gets louder and louder, and when it's loud enough, you get shunted."

"Will it happen again?"

"That depends. How many times has it happened so far?"

"I shunted over and back."

Nadir hesitated. "Then yeah, it'll happen again."

"So stop it," Skulduggery said.

"I can't. It's all about the reverberations inside her now. It's got nothing to do with me. It'll stop itself. Something like that, you're really only looking at eight or ten trips before the echo gets too weak to affect you. You've taken two trips so far, so you have between four and six left to go, and that's it."

"Somewhere between?" Skulduggery said. "So it might not be an even number? It might not be four or six trips it might be three or five. Which means she could be shunted over there and left stranded."

"Oh, yeah," Nadir said. "Didn't think of that."

"How much time before I get shunted again?" Valkyrie asked.

He shrugged. "This kind of thing sets up its own rhythm."

"If Detective Cain gets shunted over there," Skulduggery said, "and doesn't shunt back within an acceptable time frame, we'll need to go over after her. And you'll be taking us."

Nadir leaned back in his chair. "Will I, now? Well, as an integral part of the rescue mission, I might have a few conditions of my own. I'll let you know if I'm available." He smirked.

Skulduggery placed both hands on the table and leaned over. "You've heard about me. You've heard about the things I've done."

The smirk faded a little. "So?"

"So the stories you've heard are nothing compared to the truth, and the truth is nothing compared to what I'll do to you if something happens to Valkyrie. I'm the worst enemy you could ever make, Silas. Look at me and answer honestly. Do you believe me?"

Nadir swallowed. "Yeah."

"Good."

They left him there, and headed for the Accelerator Room. "You're going to have to stay above ground," said Skulduggery. "When you shunt, you stay in the same place, you just switch dimensions. We don't know if the other dimension has this Sanctuary. If it doesn't, you'll shunt right into compacted rock and earth."

"And if I'm above ground, I might shunt into a building or a tree or a person. It's dangerous either way."

"True, but-"

"We carry on as normal," she said. "We have to. We're too busy not to. Tell you what, when Lament gets the Accelerator working and when Kitana and Doran and Sean are in shackles, we'll find somewhere nice and safe and I'll stay there for however long it takes. OK?"

"For however long it takes. Even if it's weeks."

She nodded. "I'll bring a long book with big words."

"Deal," he said. "And if you shunt in the meantime without me, just stay in the one spot, stay out of sight and stay out of trouble until you return. Do you think you can do that?"

"Me? Stay out of trouble? Shouldn't be a problem in the slightest."

The Accelerator pulsed like a heart was beating from somewhere deep inside, sending a warm, gentle light through the veins of circuitry that passed beneath the skin of the machine. The white disc that had lain at its base now hovered centimetres off the ground, suspended by an unknown force, forming a sort of raised platform, what Lament was calling a dais.

Lament and the others worked in silence to disconnect the Cube from its power source. He and Kalvin may have been the engineers of the group, but both Lenka Bazaar and Vernon Plight proved themselves to be the equal of any scientist. Valkyrie reckoned that's what thirty years stuck in a mountain would do to you.

Ravel paid frequent visits to what was now known as the Accelerator Room, eager for progress, but Lament would not be hurried. The Cube would only be transferred into the Accelerator once all precautions had been taken. Valkyrie watched until she grew bored. Admittedly, it didn't take long.

She went exploring. There were lights down there now, and heat was starting to be pumped in and it wasn't quite as damp as it had been, but it was still pretty squalid. As she walked, she wondered how many hidden tunnels she was passing. Roarhaven was known for its secrets, after all.

"How are you feeling?" Skulduggery asked from behind her.

She turned, holding out her hands. "I feel great. Don't I look great?"

"You look wonderful," he said. "A little cold, maybe."

She glowered, and hugged her bare arms. "I can't believe that wretch has my jacket. I'm going to break her face next time I see her."

"They gave you quite a going-over."

"I've had worse."

"Have you?"

Valkyrie shrugged. "It's nothing I can't handle. What about you?"

"The only thing that still hurts is my pride."

"Yeah. Three amateurs, like. That's just embarrassing for you."

His head tilted. "Embarrassing for me, but not for you?"

"I'm not the one with the reputation in tatters."

"I think my legend will survive, thank you very much. We underestimated them and that was our mistake. The magic has woven in and around their reflexes and instincts they don't need to know how they're doing something, they just do it. Next time we'll be prepared."

"Next time I'm breaking her face."

Skulduggery nodded with approval, and then turned his head to her. "You know, with everything that's been going on, we haven't had a chance to talk about Fletcher."

She laughed. "When do we ever talk about Fletcher?"

"Hardly ever," he admitted, "but you haven't seen him in a while, and he comes back, and he has a girlfriend..."

"How do you know he has a girlfriend?"

"He told me."

"Oh. Yeah, he has. She's nice. Myra, her name is."

He nodded, didn't say anything.

She arched an eyebrow. "What?"

"How do you feel about that?"

"Are we seriously talking about how I feel about my ex-boyfriend? Do we have nothing better to do with our time? Aren't there murders we need to solve?"

"You just look like you need to talk, that's all."

"I'm fine. My God, I'm grand. It's not like he's the love of my life. We broke up, he has a new girlfriend, that's what happens."

"You don't have a new boyfriend."

"Thank you for pointing that out."

"And Hansard Kray doesn't seem interested."

"Oh... my God... you can stop making me feel better now."

"It's just, if you were feeling somehow... unattractive..."

"Sorry?"

"I don't mean unattractive," he said quickly. "I mean, if you were thinking that maybe you'll always be alone-"

"I wasn't thinking that," Valkyrie said. "I wasn't thinking that at all. But now I am. Now I definitely am. You think I'll always be alone?"

"That's really not what I meant."

"Then what did you mean? My God, Skulduggery, just tell me. Be honest with me. Fletcher's moved on, Hansard doesn't fancy me..." She buried her face in her hands. "Oh, God, I'm seventeen years old and no one will ever love me. I'm going to be alone for the rest of my life. I've missed my chance. I've missed my chance at happiness. I'm an old maid. Oh, God..."

Skulduggery folded his arms. "You're mocking me."

She took her hands down. "Well, duh."

"I was only trying to be sensitive."

"I don't need you sensitive, Skulduggery. I need you aloof and irresponsible and arrogant. That's why I love you. That's why I let you hang out with me."

"I'm truly blessed."

She grinned. "You love me, too. Once you admit it, everything will be better."

"They're about to hook up the Cube to the Accelerator," he said, and turned and walked off.

She followed. "You can't run from your feelings."

"I can walk from them."

She laughed, and a blue light shone from behind them. They turned. A curved wall of transparent blue energy filled the corridor behind them. Valkyrie frowned. "And what's this now?"