"What do they say about Argeddion?"

"Nothing. Absolutely nothing. Just his name and that he appears in their dreams."

Skulduggery considered the gaoler. "We'd like to speak to one of these inmates, if you wouldn't mind. Preferably one of the more lucid ones. Do you have the list there?"

Skulduggery walked up to him, Valkyrie following behind.

"What does any of this have to do with Nadir?" asked Mien.

Skulduggery didn't get a chance to answer. An alarm rang out, so sudden and so loud it made Valkyrie jump. She looked around, looked back, and a wall of glass slammed down in front of her, sealing her off from Skulduggery and Mien. At that moment, sigils faded up along the walls, and she felt her power dampen. On the other side of the glass, Skulduggery looked at her, then spoke to Mien, who was clearly agitated. Valkyrie couldn't hear a word of what they were saying. Mien hurried away, and she raised an eyebrow at Skulduggery.

His jaw moved up and down. She pointed at her mouth.

His hand went to his collarbones, and a false face spread over his skull. This time, she could read his lips.

Don't panic, he said.

I'm not, she mouthed back.

He knocked on the glass. We can't break through this. We'll get you out in a second.

Cool.

Mien appeared behind Skulduggery. He looked even more agitated than before. Skulduggery exchanged words with him. A lot of words. Still the alarm rang out. Finally, Skulduggery turned back to her. Good news, he said. You can start panicking now.

She glared. He took out his phone and rang her.

"It seems that a riot has broken out," he said when she answered. "That prisoner who was released back into the general population evidently started some trouble. Now, before you begin to worry, the section of the gaol that I'm standing in is completely secure. No problems here. I'm not in any danger whatsoever."

"And the section I'm standing in?"

"Well," he said, "the important thing to remember is that I'm perfectly safe."

Valkyrie sighed. "I'm stuck in here with the bad guys, aren't I?"

"Or you could be glass-half-full about it and say that they are stuck in there with you. Which might make you feel better."

"It really doesn't."

"Mien's working on a way to isolate this corridor from the rest of the gaol in order to get the door open, but it might take oh, do you mind holding on for a moment? I have another call coming in."

She stared. "What?"

The line went silent, and she watched Skulduggery talk into his phone. She knocked on the glass. He held up a finger as he spoke.

She stood there and fumed.

Finally, he nodded to her, and she raised her phone to her ear.

"You look angry," he said.

"You put me on hold."

"For a very good reason."

"You put me," she said very, very slowly, "on hold."

"And judging by the look on your face, and what a pretty face it is, I'm going to be very sorry about that later on. Back to now, though, that was Ghastly. A few moments ago I called him, asked him to get a Sensitive to run a remote scan of the facility, just out of curiosity. I wanted to know where the power was coming from to keep this place oscillating between dimensions. It's coming from deep down in the lower levels."

"Yay," Valkyrie growled, still glaring.

"Before his apparent demise, Silas Nadir was a Dimensional Shunter. He could move himself, or other people or objects such as the bodies of his victims into different realities. They call it shunting."

"I gathered that. You think he's still alive and he's being kept in the basement, where he's constantly shunting this whole building around."

"Yes, I do."

"And you can't get to the basement, can you? But I can. And that's where you want me to go. You want me, a seventeen-year-old girl without any magic or protection, to wander through a prison while the convicted murderers and God-knows-whats are running around having a riot. Is that what you want me to do, Skulduggery?"

"It is."

"And is this a safe thing for me to do, Skulduggery?"

"It isn't. But there are two very good reasons why you should do it anyway. Reason number one, it's our chance to look around without Mien's interference. Reason number two, the corridor you're standing in will soon be filled with convicts."

"How do you know?"

"You heard Mien. The front door is the only exit. This is the only corridor to the front door. There are bound to be some convicts who are going to try and take advantage of the distraction the riot provides."

"So I should go now, before they get here."

"Indeed you should. Keep your phone to your ear, I'll guide you."

"How do you know the way?"

"I glanced at the schematic on the way in."

"You memorised it?"

"Glancing, memorising, it's the same thing. You should really, really go now."

She took a deep breath. "Get this door open and come after me."

"Count on it."

Valkyrie looked at him, then turned, ran down the corridor and round the corner.

"At the junction," Skulduggery said, "turn right. Can you see anyone?"

"No," she said, moving fast, "not yet."

"Hopefully, we'll be able to keep you out of sight. You won't be in the prison area as such but then neither will the prisoners, so..."

"I have to admit," she said, "I'm worrying."

"Perfectly understandable. I'm heading to the security room. I'll be able to see you on the monitors soon enough. You should be seeing three doors ahead of you."

"Yeah, I've just reached them."

"Take the second one to your left."

She tried it. "It's locked."

"Kick it open."

"It's a sturdy door, Skulduggery."

"But it's not reinforced. It's not designed to keep any prisoners in or out, it's designed to keep unauthorised personnel from going places they don't have clearance for. It's just a simple door with a simple lock. And you've got very strong legs."

She looked at the door. "See, this is where a gun would come in really handy." She kicked. "Ow! Oh, God!"

"Are you OK?"

"Kicking doors hurts! Even with Ghastly's boots!"

"Put your weight behind it. Pretend the door is someone who has really annoyed you recently."

"Can I pretend it's you?"

"I really don't see how that would-"

She kicked it, and the door burst open. "I'm in," she said, closing the door behind her. "And that really hurt my foot. I'm in a room with machines along the walls. Lots of blinking lights."

"Do you see the ventilation duct along the floor?"

She froze. "Please tell me I don't have to crawl through that."

"I'm afraid you do."

"No. I can't. It's too small."

"The measurements are-"

"I get claustrophobic! You know I do! Especially after the caves last year, with all those things and I couldn't move my arms and they were in my hair and-"

"Calm down."

"I'm not getting in there, I'm just not."

"You'll be able to fit," he said, his voice gentle. "You will have space to move. You won't be trapped."

"I can't."

"Valkyrie, listen to my voice. I know you don't want to, I know you don't think you can, but you don't have a choice. I'm in the security room now and I can see the monitors. The prisoners are swarming the building. You can't let them catch you."

She dropped to her knees at the duct. "How do I even open it? It's screwed in place."

"You're going to have to prise it open. Is there anything you could use?"

She looked around. "There's a bench here with things on it, bits of machinery and stuff. And some tools. There's a screwdriver! I could use the screwdriver to prise it open!"

"Yes," Skulduggery said, "or you could use it to unscrew the screws."

"Oh, yeah," she muttered. She grabbed the screwdriver, hurried back to the duct and got to work.

"The Cleavers are doing a good job with the riot," Skulduggery said, "but there are prisoners running everywhere. How are you doing?"

"One almost... OK, it's out. Three left."

"The prisoners have reached the security door."

The screwdriver kept slipping out of the groove. "The glass door?"

"Yes."

"So they're really close."

"Yes."

Her mouth was dry. "The moment they realise they can't break through that door they're going to turn around, find their way through here."

Skulduggery hesitated. "They've turned around, Valkyrie."

Two screws left.

"They're heading towards you."

The screwdriver slipped again.

"Valkyrie..."

"I'm going as fast as I can." Her heart hammered. The third screw fell. "One left."

"Valkyrie," Skulduggery said, "you're going to have to be really, really quiet."

She heard voices, and running footsteps. She turned, screwdriver clutched like a knife, waiting for the door to burst open.

The voices passed the door, started to grow distant.