The Plumleigh-Teignmotts looked as if they would like to object.

“Please, Dimity. Please?” Sophronia was more earnest than Dimity had ever seen her.

Dimity nodded, her round face doll-like in its seriousness.

Sophronia turned to Sidheag. “Keep an eye on them, too?”

Sidheag nodded. “Kidnapping?”

“I’ll explain later.”

Sidheag nodded again. Sophronia blessed Lady Kingair’s military upbringing. The girl knew how to follow orders.

“Oh, and Dimity, as you exit, could I have a little diversion?”

Dimity pursed her lips. “Of course. What kind—”

Mademoiselle Geraldine clapped her hands, and all the girls turned to face her expectantly. “Line up by year for the counting. Debuts this side, midranks there and there, oldest girls that side, boys at the back.”

There was shuffling while they did as they were told. Felix took it as an opportunity to brush close to Sophronia.

“What’s going on, do you think?” he asked.

“You mean you don’t know?”

“No, why should I?”

“Your people are involved.”

“What do you mean, my people?”

Sophronia gestured below, where a great number of benches were being put out on the green near the skeleton of the Crystal Palace. This was nothing like Giffard’s landing earlier that day. This was a private nighttime affair, and the constabulary were present to ensure it stayed private. These were not any old crushers, either. They wore the silver and wooden weaponry of men who specialized in the supernatural. Not that there would be much activity in Hyde Park so early at night. After supper was a time used to dress. Things weren’t actually supposed to happen at nine o’clock in the evening. It was a most unfashionable hour to run a test, even covertly. No wonder Mademoiselle Geraldine was disgruntled.

Under the moon’s bright light Felix could see what Sophronia meant by her slur. His friends were indeed seated below. A goodly number of gentlemen wore top hats with green satin bands about the crown. There were others as well—a group of well-dressed dandies, some scruffy types who could only belong to a nearby werewolf pack, and two pale, debonair gentlemen who must be vampires. The potentate sat with them.

Sophronia noted that the sky was becoming overcast. Not with clouds but with airships. A small armada approached and hovered at a distance. There were little airdinghies with four small balloons and sails up high in the middle—flywaymen. There were larger, proper dirigibles, a matched set with dark-colored balloons—sky pirates or private-airs. No doubt Madame Spetuna and Bumbersnoot are up there somewhere watching.

Mademoiselle Geraldine’s Finishing Academy sunk down as low as possible, proving that the scaffolding all around it was quite fake. A counting was conducted, and the staircase was cranked down. As they began shambling toward it, Sophronia drifted to one side, her eyes on the professors. Dimity gave a shriek and a wobble, veering toward the side banister of the stairway. She lurched, almost tumbling down several stories to the ground below. Agatha peeped in fear and pretended a faint backward. Sidheag made a lunge after Dimity and nearly went over the edge herself. They were doing beautifully.

Everyone burbled in perturbation. The crowd boiled upward as ladies raised on tiptoe to see what was happening. Teachers and other staff pressed forward to ascertain the cause of the commotion. Lady Linette, trained as she was, sensed the manufactured nature of the distraction and surveyed the crowd, but with over three dozen on the midship deck it was easy for Sophronia to wait until her teacher’s gaze passed her over.

The moment Lady Linette looked elsewhere, Sophronia crouched. The fashion for large hats, even at night, afforded her some protection from view. Removing her own bonnet, she made a break for the staircase that led to the upper decks. She’d be exposed if she actually took those stairs, but she could hide behind them until everyone had disembarked.

Sophronia waited patiently until blasts of steam and the sound of cranking indicated the staircase was being pulled back up. The ship lurched upward. It was safe to emerge.

Professor Braithwope was visible on the upper forward squeak deck far above. He was climbing into the contraption Professors Lefoux and Shrimpdittle had built. It fit him like those suits designed for undersea exploration. What are they called? Diving suits. Once it was fully in place, he looked a little like an oversized mechanical, only more liquid in his movements.

Sophronia made her way around to the far side of the ship, out of view from the watchers below. But not before she saw Sidheag sit next to Captain Niall, along with Dimity and Pillover.

Giffard’s aether-current floater, the Puffy Nimbus Eighteen, swooped into sight, ululating in their direction. Sophronia had once manned an airdinghy, and she knew enough to admire Giffard’s skill. Once the other airship was level with Mademoiselle Geraldine’s, the school extended a long gangplank to it, and Professor Braithwope ran across with a tightrope walker’s skill. The gangplank was drawn back and the two ships began to rise ponderously, keeping pace with each other. Sophronia had intended to check up on the sooties, but she was hypnotized by the action above her, so she stayed hanging where she was. Professor Braithwope and Mr. Giffard exchanged pleasantries, and then Mr. Giffard went back to work steering his small vessel. The two ships rose together, so high the people below became little specks. Then so did the trees of the park. Finally, London herself was nothing but a blob of twinkling lights. They were above the clouds at last, and then higher than Sophronia had ever floated. The air was glacial and the winds howled by; the propeller pushed hard against the breezes through which the school normally drifted peaceably.

Sophronia wondered if there would be a defining shift when they hit the aetherosphere. She knew that it must be close, that invisible onion skin, the thing that protected them all from the void beyond. She couldn’t believe they intended to take Mademoiselle Geraldine’s up that high. Giffard’s aether-current floater was built for the changeable humors of the upper sphere, but Geraldine’s was not.

She turned her attention to Professor Braithwope. The vampire stood stiff and straight, leaning back against the railing of the Puffy Nimbus’s one squeak deck and looking up. Sophronia could hardly fathom that he intended to enter aetherosphere. Very little was known about it, except that it was breathable but dense, not like normal air, and dangerous. Only humans had ever been inside it, and only very few of them. But no other vampire could float up even a short distance; Professor Braithwope was the exception, by virtue of his inhabiting their school. So the school had to go up with him as far as it could, keeping his tether as short as possible.

They intended all along to send the vampire, suited in his protective gear, into the aetherosphere on Giffard’s ship. He will be the first supernatural creature to enter aether. They want to know—vampires, werewolves, government, Picklemen. They all want to know: what happens to a supernatural creature in the aetherosphere? They built him a suit as a nod to safety, but they really have no idea what will occur up there.

Professor Braithwope was undergoing a very dangerous test indeed. For queen and country, the potentate had said. For science, Sophronia thought.

Mademoiselle Geraldine’s stopped rising and held steady, the propeller fighting to keep the school in place. They had gone up as high up as possible. Directly above us, thought Sophronia, must be the aetherosphere. It boggled her mind. She looked but couldn’t see anything apart from very bright stars. The aetherosphere was invisible from below, and opaque from within, or so she’d heard.

Giffard gave some kind of signal and the Puffy Nimbus bobbed up, leaving Mademoiselle Geraldine’s behind.

At first everything seemed fine. Then Professor Braithwope began to gyrate around in his mechanical suit, waving his hands about his face as if fending off a swam of attacking wasps. The mating dance of a mechanical was Sophronia’s hysterical thought.

Giffard seemed to be occupied doing battle with his navigation helm. Sophronia thought she heard Professor Braithwope scream. Then she saw him jerk wildly backward, come up against the railing, and flip right over it. At the time and for years after, she was never certain if he fell accidentally or jumped in order to get relief from invisible tormentors.

Professor Braithwope, encased in his Lefoux-made suit, was tumbling down though the air. His body was limp and there was no sound coming from him anymore.

He should be screaming, thought Sophronia, inanely. I would be screaming.

She watched, transfixed, as the vampire’s body spiraled down into the clouds and out of sight.

Then she moved. He was supposed to have had a guidance valve in that suit of his. Presumably connected to their ship’s boiler room, so they could follow him right away if anything happened. But he either hadn’t used it or it hadn’t worked, because Mademoiselle Geraldine’s still held steady.

Sophronia had never moved so fast about the hull, hurling and jumping from balcony to balcony in a frenzy, working her way down until she could climb in the hatch to the boiler room.

She had never seen engineering so busy before. It was a swarm of activity, every sootie awake and at work. There were greasers, firemen, and engineers everywhere monitoring the flurry. It couldn’t have been easy. All the boilers were burning, licks of flame coming from the fuel boxes. Steam that didn’t make its way out through the pipes filled the room, clouding the upper portions of the cavernous space and making it seem more intimate. It was incredibly hot.

Sophronia’s only thought was to find Soap. Fortunately, he found her.

“What ho, miss?”

Sophronia babbled, forgetting her manners and grabbing his arms in an excess of emotion. “Soap! The school has to go down with him! His tether will snap!” she yelled helplessly into the loud bustle of the boiler room. “Go down now! Take us down! Please!”

Soap put gentle hands on her clutching arms. “I don’t know what you’re on about, miss, but orders have to come from the pilot’s bubble.”

Sophronia panicked. She remembered only Professor Braithwope’s face when she asked him about tether limits. How terrified he had been. They needed to follow him as quickly and as closely as possible.

“Soap, who is in charge of the boiler room?”

Soap looked at her, mouth open. “What, miss?”

“Take me to him, please? Now.”

Soap lead her through the craziness at a run. Sophronia dogged him in her full dress and hat, looking as if she were about to go for a stroll in Hyde Park. Her skirts were long enough to lift up the soot dust in her wake, like steam from a machine.

They ended up at the base of a tall platform that rose up to one side of the room, allowing the man standing on its top to overlook the entirety of the activity therein.

“You stay here, Soap. No sense in us both getting into trouble.”

“Are you sure, miss?”

“Yes,” said Sophronia. No, thought Sophronia.

Soap’s face puckered in concern, but Sophronia turned her changeable green eyes on him and said, “Please.”

So he let her climb up to the dais alone.

The man who stood on the top was dirty with coal dust and wore simple clothing—jodhpurs, boots, shirt, and vest. He had facial topiary sprouting off of his chin and down his neck like a mountain goat. The beard was red, as was the man’s cruel face.

“Who are you, missy?” he barked.

Sophronia quailed a moment—he was very fierce—and then she remembered Professor Braithwope’s well-tended, if confused, facial hair and found her courage. I must send a beard to rescue a mustache! “Sir, it’s Professor Braithwope. He fell. I saw him. We must track him down or he could be permanently damaged. Please, we have to follow quickly.”

“That’s not possible, little miss. The lever hasn’t dropped. And this is no place for a young lady. Get along with you.”

“Please, listen! We must go down. We must!” This was one of those times Sophronia wished she had blackmail material. Why oh why were those lessons only for older students?

“If we were to go down, that newfangled gadget would have told us.” The man pointed to a small cradle, in which sat a guidance valve. It was partly encased in mechanisms that attached to a lever. Sophronia remembered what she’d learned about the first prototype—that it required two to communicate. This was the second, and Professor Braithwope’s suit housed the first. She remembered Vieve and her troubles convincing the sputter-skates to turn off using her guidance valve. It hadn’t worked properly because she’d needed a second valve. This, then, was supposed to have been the vampire’s safety net. Professor Braithwope, or his suit, should have alerted engineering when something went wrong. That lever should have dropped. But it hadn’t, and the professor was falling.