Rising from the night streets of UnLondon was the arc of the Pons Absconditus. It was a suspension bridge, with supporting up-down iron curves like two dorsal ridges. It should be spanning a river. It was not. Instead, it rose out of backstreets, from nowhere in particular, went over the roofs, and came down several streets away, in a different nowhere in particular.

There were few bulbs on in few windows. Occasionally, Deeba and Zanna saw four lights rush by through the UnLondon streets, two white lights at the front, two red at the back. The first time, they thought it was a car, but there was nothing there, only a glow like headlights. It was as if in the absence of automobiles, UnLondon had provided their pretty illuminations itself, to leave glowing trails in its night-streets.

The headlights veered past the obstacles that littered the abcity, some half-grown out of the tarmac, some lying ready to be used: old sofas; dishwashers; skips full of glass; chairs emerging from London, growing on their rusty legs like flowers with four stalks.

“Why’d they build the bridge here?” Deeba said.

“They didn’t,” Inessa said. “This is just somewhere people know they can find it. It’s like any bridge: it’s to connect somewhere to somewhere else. That’s what bridges are for.”

There was no one in the streets. The streetlamps shed a dim, dirty light. Below the bridge were a load of dustbins. The corrugated metal cylinders were about half Zanna’s height. They all had their round lids carefully on.

“Now,” said Inessa. “We need to get onto the bridge, to see the Propheseers.”

“It comes down over there,” Deeba said. “Behind those houses.”

But behind those houses, there was another row between them and the end of the bridge. Frowning, Zanna and Deeba turned another corner, and came to a sudden stop.

The bridge still came down close to them— but still just behind another brick row.

“What’s going on?” Zanna said. “We’re not getting any closer.”

Walking under the Pons was no problem. Zanna and Deeba went back and forth below it several times, and it stayed politely immobile. They tried to walk onto it, and its ends stayed stubbornly one or two streets beyond them. They came at it slowly, quickly, sneakily, in full view. It was always just out of their reach.

Zanna and Deeba and the Slaterunners stopped in the dark under the bridge, among the dustbins. Deeba stroked Curdle.

“It’s like a rainbow,” Zanna said. “You can’t reach its end. How are we supposed to get on?”

Something flitted quietly through the air. They tensed, but it was just a scrunched-up piece of paper, dropping from the bridge. It settled among the dustbins.

“I wondered how they kept undesirables off,” Inessa said. “I didn’t realize the bridge was shy.”

“Yeah,” Deeba said. “Looks like they don’t need any guards.”

“Actually,” Inessa said, “I think they have them too.” She pointed.

One by one, dustbins around them were standing up.

There were seven or eight of them. A pair of skinny legs jutted from each of their round metal undersides. From their sides sprouted thin, muscly arms. Their lids teetered, then tilted. They opened just a slit. Inside was darkness, in the thick of which were eyes.

The dustbins stepped closer.

They moved with an athletic precision. The Slaterunners circled warily, ready for attack. But the bin in front raised its hand, and spread surprisingly dainty fingers, as if to say, Wait. It tapped the side of its lid, and cupped its hand in an ostentatious listening motion. There was that sound again. The noise of boots.

“They’ve found our trail!” Inessa said.

The dustbin put its finger to where its lips should be. It made quick gestures, and two of its companions ran fast and soundlessly out of the shadows.

In the light of the streetlamps they retracted their arms and legs with a faint shlp, leaving only grubby stains where each limb had been. They were instantly disguised— just a pair of dustbins. After a moment they sprouted limbs again. They stood in karate poses. Then they opened their own lids, reached into their own dark interiors, and drew out weapons.

One took out a sword, and the other two pairs of nunchucks, which Zanna and Deeba recognized from martial-arts films. The two dustbins ran off towards the sound of the pursuers, disappearing in shadows.

You: the dustbin leader pointed to Zanna and Deeba, then pointed straight up, to the bridge above them. Beckoned.

“It wants us to go,” Deeba said.

“Not without the Slaterunners,” Zanna said. “They’re the ones got us here…”

“It’s alright,” Inessa said. “I’ve no business with the Propheseers, whereas you…you’re expected. You go, Shwazzy. We need to get back to the Roofdom. These are the Propheseers’ protectors. They’ll get us out of here safely. We’ll be alright, and so will you.”

Zanna and Deeba gave each of the Slaterunners a hug.

“Thank you,” Zanna said.

“Take care of yourself,” Inessa said. “Shwazzy…we’re counting on you. All of us.”

The dustbin crept, Zanna and Deeba behind it, through the same streets that they had just walked. This time, however, the end of the bridge grew closer with every turn.

“How did you do that?” Zanna muttered. The dustbin motioned her to silence.

The Pons Absconditus rose in front of them. To either side were the doorless backs of houses. UnLondoners might be able to see the bridge from their rear windows, but without a guide, they’d have no success reaching it.

It rose like the back of a sea serpent. At its apex were moving figures.

The girls’ dustbin escort walked them onto the bridge.

“Finally,” said Zanna. “The Propheseers.”

“We can go home, ” Deeba almost gasped.

“And find out the truth,” said Zanna quietly.