“Over here,” Glain called. She was leaning half her weight on Thomas, but she had a look of elation on her face. “I think these are steam tunnels.”

Jess felt a wave of disquiet. “Did you find a way out?”

“There’s a staircase leading up. It’s barred with a grate,” Thomas said. “Welded shut, with the symbol of the English lion on it. London Garda?”

“Find something to force it,” Jess said, and began looking himself. “We may not have much time.”

“Why not? What is it?” That was Dario, who’d finally gotten up from his spot against the wall. Jess picked up a piece of rotten wood and tossed it aside without answering. “Jess, wait. I can explain—”

“I’m not listening,” Jess interrupted. “Look for something to break those welds. Hurry.”

“Why?” Santi asked.

“Because if Glain’s right, these tunnels vent scalding steam off of the city boilers. We need to break out of here. Quickly.”

“How often does it vent?” Wolfe asked.

“I don’t bloody well know! Every day? Every hour? The point is, we need to move. Now!”

That ended the questioning.

It was Khalila who came up with the solution, when a search failed to turn up anything else. She made an impatient sound, grabbed Jess’s weapon, and said, “Make it safe. Quickly.”

He did, sliding the safety switches and removing the cartridge, and she jammed it into the grate. “Now, Thomas. You’ve got the best leverage, I think.”

“I’ll try.” He sounded doubtful. His best effort popped half the weld loose, but then he stepped away, panting, flexing his arms. “I’m sorry. I’m still too weak.”

Santi stepped up and took a try and almost got it. One last try with both of them shattered the last of the welding, and the grate swung open with a rusty, stubborn shriek of hinges.

“Stairs,” Glain said gloomily. “Better let me go last. I’ll just hold you up.”

Khalila shook her head. “You come with me,” she said, and put her shoulder under Glain’s. “We’re not leaving you behind, so don’t start.”

They climbed up. When Dario moved toward the stairs, Jess shoved him back. Hard. “Not yet,” he said. “Why did you do it?”

Dario coughed, spat out black ashes, and wiped his mouth. “Do what? I went to the embassy. I thought I’d get help for us from my father. Instead the embassy called the Artifex.”

“And you sold us out. Just that easy. Coward.”

“No.” Dario wiped angrily at his eyes. “I would have given my life. But he had Khalila’s family, Jess. I couldn’t let him . . . I told him where you would have gone, to London, but you didn’t show up there. He asked me where else you would go. I said you would try to find the Black Archives. Jess, I didn’t know they were in the Iron Tower.”

Jess was silent. He’d effortlessly believed that Dario had turned on them. Why was that? What had Dario done to deserve that, really? Would he have done any differently with Khalila’s family at stake?