“Let me do this,” Alek whispered again.

Deryn rolled her eyes. “Don’t be daft. I know every squick of this ship. You’ve never even been in the laboratory.”

“But you can’t just sneak into a man’s room while he’s sleeping,” Alek said, his voice breaking from a whisper.

“And you can? You’re a barking prince. I hardly think that qualifies you for burglary.”

Alek started to sputter something else, but Deryn ignored him, glancing up and down the hallway. After a day that had included a rope-and-winch landing and twenty-eight unexpected new passengers, the exhausted crew was mostly asleep, the airship’s corridors empty and dark.

“Just stay out here and keep quiet.”

“Mr. Tesla is quite unbalanced,” Alek whispered. “Who knows what he’ll do if he wakes up? Volger said his walking stick was quite dangerous.”

“Aye, there is that,” Deryn murmured. Tesla had promised the captain that he wouldn’t fire the stick inside the airship. But what if she startled the inventor, and he forgot that he was hanging from a giant bag of hydrogen? “I’ll have to make sure I don’t wake him, I suppose.”

“Why don’t we simply tell Dr. Barlow that he’s got something in his cabin?” Alek whispered. “The ship’s marines can search for it in the morning.”

Deryn shook her head. “You know what a sneaky-beak the lady boffin is. She wants it all done quietly, so Tesla won’t know she’s on to him.”

“Of course. The simplest path is completely beyond that woman.”

“Listen, if you want to help, wait out here and give the door a wee scratch if anyone’s headed this way.” She pointed at the beastie. “And keep your eye on Bovril. It’ll hear any footsteps before you do.”

“Don’t worry. I’m not moving from this spot.”

“Except to hide if you hear anything.” Deryn recalled the whispering sound Bovril had made as they’d left the belowdecks. “If any of Tesla’s Russians saw us down there, they might pop up to tell him.”

Alek opened his mouth to protest again, but Deryn silenced him with a stern look, pulling Dr. Barlow’s keys from her pocket. The largest was labeled LABORATORY, and fit perfectly into the lock.

“Shush,” Bovril said with a quiet, anxious rush of breath.

As the door opened, a wedge of the corridor’s green light spilled into the room, and Deryn’s breath caught. Of course, being discovered right away would be easiest. She was simply a dutiful middy checking on an important passenger.

But Mr. Tesla was asleep in his bunk, his breathing heavy and slow. The moon shone through the window, three quarters full, and the glass instruments that Dr. Busk had left behind glittered with the moon’s pearly light.

Deryn stepped inside and leaned back against the door, her heartbeat taking up residence in her bruised foot. The door shut behind her with a soft click, but still Mr. Tesla didn’t stir.

A shiny leather suitcase lay open on the floor, revealing a neatly folded white shirt that glowed in the moonlight. The electrical walking stick lay on a laboratory bench, its handle pulled off to reveal a pair of wires. As Deryn’s eyes adjusted, she saw they were connected to the airship’s power lines. So the bum-rag was recharging his stick, despite his promise to the captain.

Deryn took a few slow steps into the room, her foot still pounding from the contraption landing on it. She knelt by the suitcase and slipped a hand beneath the shirt on top, feeling layer by layer. Nothing but clothing.

She frowned, looking about the room. Dr. Busk had cleared most of his boffin gear away, so the lab wasn’t in its usual cluttered state. There wasn’t much space to hide anything, at least not anything big enough to create an explosion forty miles across. But the little slivers of lightning had pointed straight at this cabin, so whatever Tesla had found had to be here.

She swore under her breath. It was just like the lady boffin, sending Deryn to search for something without saying what it was.

As she knelt there pondering, a soft scratching sound came from the door. It was Alek, alerting her that someone was coming. . . .

There was nowhere else to hide, so Deryn dropped to her hands and knees and scuttled beneath the bed.

She waited there in the darkness, her heart pounding. There were no sounds from the corridor, nothing except the rush of wind and Mr. Tesla’s steady breathing.

Maybe it had been only a crewman walking past. . . .

But then a soft knocking came from the door. Deryn squeezed herself farther under the bed as the sound grew louder. Finally the door opened, spilling wormlight into the room.

Deryn swore silently—she hadn’t locked the door behind her.

A pair of fur-lined boots strode to the side of the bed, and she heard Tesla’s name amid a stream of whispered Russian. Tesla’s voice answered, sleepy and confused at first. Then a pair of bare feet descended before her eyes, and a quiet conversation began in Russian.

Lying there, Deryn realized that something was poking into her back. She reached a hand around and felt an object wrapped in a canvas sack. It was as hard as stone.

Deryn swallowed. This had to be what she was looking for, but it wasn’t much bigger than a football. Would Tesla have come six thousand miles to find something so small?

She would make too much noise if she turned over to take a closer look, so she slowed her breath and waited, staring at the fur-lined boots and trying to ignore her own throbbing foot.

Finally the whispered conversation ended. The boots walked away and through the door, and the pair of bare feet shifted as Tesla stood up. Deryn clenched her fists. Was he going to check on his precious cargo beneath the bed?