“I know!” said Obaday. “Hard to believe. But yes. I think we need to.”

Zanna and Deeba looked at each other. They didn’t speak, but messages went between them in a series of looks and raised eyebrows: What’s the big deal with a bus? Don’t know…

“I’ve got the fare,” Obaday said. “They never turn anyone away, but it’s traditional to pay what you can.”

They were joined at the stop by an elderly woman in a coastguard’s uniform, and a hulking figure in a dress at whom Zanna and Deeba had to force themselves not to stare. It was a lobster, waddling on two stubby legs, clacking her pincers.

Obaday looked at his watch, leaned against the pole, and began to read his sleeve. The girls watched the sky. A sliver of the hoop-sun was visible over the roofs. Troupes of starlings, pigeons, and crows crisscrossed in front of the clouds, in rather more organized fashion than they ever seemed to manage in London.

“Look,” said Zanna, pointing. There were other birds among them, half-familiar from pictures, like herons and vultures. There was at least one thing in the air that didn’t look like a bird at all, something that caw ed enormously as it disappeared.

“So,” Deeba whispered, knocking the post of the bus stop. “What do you think’ll turn up?”

“Don’t know,” said Zanna.

“A load of camels?” said Deeba.

“A boat?”

“A carriage like in Sleeping Beauty?”

“A sledge?”

The girls’ smiles froze when they heard the familiar coughing of a big engine approaching. A double-decker red bus turned the corner.

“It’s just…” said Deeba.

“It’s a bus,” said Zanna.

Obaday Fing looked enraptured.

“Isn’t it magnificent ?” he said.

The bus looked severely battered. Where it should have had a number was instead a strange sign that might have been a drawing of a roll of paper or might have been a random pattern. It was an old-fashioned Routemaster of the type that had been retired from London, with a pole and an open platform at the back, and a separate little compartment at the front for the driver, a woman in an antiquated uniform and dark glasses.

“The helmswoman,” said Obaday. “And with her one of UnLondon’s champions. Protectors of the transit, the sacred warriors.”

“Morning,” said a man, jumping out of the vehicle.

Obaday whispered, “The bus conductor.”

The conductor wore an old-fashioned London Transport uniform. It had been torn and fixed many times, and it was clean, but scorched and stained. Strapped to his front was a metal contraption, on which he drummed his fingers. He wore beads, and charms, and a copper truncheon on his belt.

“Mrs. Jujube,” the man said, pushing back his cap and bowing to the elderly woman. “Always a pleasure. Manifest Station again? And madam?” He inclined his head at the lobster. “Let me guess…the estuary? You know you’ll have to change buses? Please, go on in. And sir…” He turned to Obaday.

“This is, I must, I cannot tell you,” Obaday stammered. “It is an honor, a real, I cannot, I am overcome! On behalf of all of UnLondon—”

“Well,” said the uniformed man, in what sounded like polite boredom. “You’re very kind. May I ask your destination?”

“I am Obaday Fing, and this is my associate Skool, and this is Deeba, and this —” He swept his arm at Zanna. “— is the reason for our journey. Your route takes us towards the Pons Absconditus, I think?”

Obaday rummaged in his pocket and brought out a handful of money. There were francs and marks and ancient English pound notes, and colorful currency Deeba and Zanna didn’t recognize. “One young lady has her own ticket.”

Zanna held out her travelcard. “This, ” said Obaday, “is—”

“The Shwazzy,” the conductor whispered. He grabbed the travelcard and examined it.

“I know that look,” he said to Zanna, smiling. “Astonished, bewildered, excited, frightened…awed. That’s the taste of the first few days in UnLondon. It takes one who’s swigged it to recognize it. Shwazzy, it’s a great honor.”

“You recognize it…?” Zanna said.

“You came here, too?” Deeba said.

“Where d’you think I got this?” he said, pointing at his uniform, and the box around his midriff. “Where you two from?”

“Kilburn,” said Zanna.

“Ah. I’m a Tooting boy originally. Joe Jones— pleased to meet you. I went abnaut— that’s what it’s called, crossing down, or up, or sideways, from there to here— and came to UnLondon, what, must be more than a decade ago.”

“You did?” said Zanna. “Thank God! You can explain things.”

“We dunno what’s going on,” said Deeba. “We need to get back, I want my mum and dad…”

“Hey, Rosa!” Jones shouted, and the driver leaned out of her window. “See who we’ve got on this trip?”

She peered over the top of her glasses.

“Blond…” said Jones. “Young lady. From out of town. As things are getting nasty in the abcity…”

Rosa’s eyes grew wider and wider.

“That is never the Shwazzy !”

Zanna and Deeba looked at each other.

“Oh my lord!” Rosa went on. “I heard rumors from the old place that something was happening, on the drivers’ grapevine…one of them even said she’d tracked the Shwazzy down to a café! But I thought it was just foolishness…But it’s finally happened! It’s time!”

“It is indeed!” the conductor said. “And it’s down to us to get her to the Pons Absconditus.”

“So, she’s going to fight for us! She’ll fix things!”

“Hold on,” said Zanna. “I don’t know anything about that…”

“What’s the holdup?” the elderly woman shouted.

“Coming, Mrs. Jujube!” Joe Jones spoke quietly to Obaday and the girls. “We should be careful who knows about this. There are…those who’d like to get in the way. The Pons is a few stops away. We’ll go as usual, so no one knows anything’s up. Get you there in a few hours.

“Please.” Jones closed Obaday’s fingers around his money without taking any. “You’re escorting the Shwazzy. Now remember— not a word. As far as anyone’s concerned, you’re just regular petitioners, come to ask the Propheseers a question. And what about that? Is that with you? Does it have a name?” He pointed at the milk carton, hesitating by the bus’s platform.

“Yes,” Deeba said. “It’s called…Curdle. Come on, Curdle.”

Zanna crossed her arms and raised her eyebrows.

The carton leapt happily inside after them.

“Curdle?” whispered Zanna.

“Oh shut up,” said Deeba. “Just get on with being Shwazzed, will you?”

There were a few other passengers on the bottom deck, oddly dressed men and women and a few even odder other things. As they always did on buses, Zanna and Deeba headed for the staircase to the upper level. The conductor stopped them.

“Not this time,” he said. “Wait a bit.”

He rang the bell, and the bus moved. Obaday and Skool sat, but Zanna and Deeba stood next to Jones on the platform at the back.

“Our next stop’s Manifest Station,” he said. “We’re heading straight there.”

“Not straight there,” Deeba said. She pointed through the front window. “I mean, there’s a wall in the way.” They did not seem to be slowing down.

“We’re going to hit it,” said Zanna. The bus gunned straight for the bricks. Deeba and Zanna winced and closed their eyes.

“Hold tight, please,” Jones shouted.

There was a hissing sound, the flapping of heavy cloth, and the thrumming of ropes. Zanna and Deeba opened their eyes again, hesitantly.

A tarpaulin bulged from the bus’s roof like an enormous fungus. It inflated into a huge balloon, tethered by ropes from the upper windows. The bus sped up, and the rugby-ball-shaped balloon stretched longer than the vehicle beneath it.

There was a thump behind them, as if something had hit the vehicle’s rear, a scuffing like an animal ascending the metal. Deeba and Zanna turned in alarm, then gasped and rocked and held on, as with a stomach-jolting tug, the bus started to rise.

Dangling below the balloon, it passed over the wall, leaving a threadwork of streets and buildings below, ascending over UnLondon.