In this extract from a yet-to-be-named children’s novel, Zen and Gus are twins who are hunting for their father, and they’ve just arrived in a part of the world where flying carpets act as taxis. They have smuggled in a message written in invisible ink on a handkerchief.

An unsympathetic official (who is not allowed to use taxis in the course of his work) has picked them up.

Gus fumbled in his head for an answer, and remembered Eddie’s gifts.

‘We have a letter of introduction.’ He pulled the handkerchief out of his pocket and put it on the table.

Inspector Tidswell picked it up and smoothed it out; a simple white handkerchief.

‘My brother’s a bit slow in the head,’ said Zen. ‘He doesn’t mean anything by it.’

‘Really, it’s written in invisible ink, we need to do something …’ said Gus, trailing off as he became aware that they didn’t actually know what it was that would make the ink visible, that they’d never got the explanation.

Zen shrugged as if to say, ‘See, he really is crazy!’

Inspector Tidswell folded the handkerchief and dabbed his sweaty forehead with it.

‘I don’t know if you’re mad or bad or both,’ he spat out, tucking the handkerchief in his pocket. ‘Even the dullest fool wouldn’t tell me they’d been smuggling things through the passages. Well you can explain yourselves to the Great Council; let them decide what to do with you. They sit in four days, you’ll be detained at the Council building until then.’

He spoke to the guard.

‘I’ll take the prisoners and I’ll take them by taxi and the council can stuff their rules up their nostrils.’

He marched the twins over to a taxi boy. Gus recognised him, Riley, the one who’d given them directions.

Riley haggled over the price.

Inspector Tidswell was not happy.

‘Outrageous. Moving prisoners is official business, and you should be doing it free as a service to the city.’

Riley rolled out his carpet. It was a blue one, rather patched and very dirty.

‘You two, sit in the middle.’

There was no opportunity to bolt.

Inspector Tidswell kept a beady eye on the twins as he searched for a clean spot for himself. Finding none, he reached into his pocket and pulled out the handkerchief, which he spread out with great care at one end of the carpet.

He awkwardly settled himself to sit, cross-legged, on it. His trousers rode up to reveal the scrawny flesh of his ankles.

‘Well what are you waiting for?’

He snapped his fingers at the taxi boy, who kneeled on the far end and murmured a few words to the carpet. It quivered and rose, ponderous, into the air, and then headed off.

‘Make this filthy thing bigger,’ Inspector Tidswell said.

Riley met Zen’s eye while he answered.

‘Can’t sir, heavy load.’

There was that same feeling of gliding silent and unnoticed while the people below haggled and purchased and laughed, or hung out washing or stood around chatting. A welcome breeze blew in their faces, and now that there was no possibility of escape, Inspector Tidswell ignored the twins and spent the time staring into the distance and plucking at his collar.

Zen was trying to memorise the route they were taking. This carpet was sluggish and it was flying low, mostly above a river.

Inspector Tidswell seemed very close.

Yes, she was sure he was closer than he had been. If she looked sideways from the corner of her eye, she could see that the carpet was drawing in, almost imperceptibly.

She looked at Riley, and he winked at her.

Zen prodded Gus with her foot, careful not to attract any attention from the Inspector, who hadn’t spotted yet that the carpet was shrinking.

Gus caught on immediately, and shuffled towards the taxi boy.

Little by cautious little, Zen and Gus moved towards the end of the carpet, trying to maintain the distance between themselves and the Inspector.

It seemed impossible that he wouldn’t notice as the carpet continued to contract, but finally the three of them were squashed up so close together that Gus’s elbow was digging into Zen’s side and Riley’s big feet were hanging over the edge.

Riley mimed to them ‘hold on’, so she took a firm grip on the side. She could see that Gus was doing the same, when suddenly Inspector Tidswell realised what was happening. His eyes widened and he took a deep breath, ready to shout.

Riley yelled something and then the carpet jolted and juddered and shrank into the size of a doormat.

The Inspector sat cross-legged in the empty air for a moment, and then he toppled sideways, shout still stuck in his open mouth. Zen could see that the handkerchief was clinging to him, and she watched Gus stretch out a casual hand and pluck it off the seat of his pants.

The Inspector flipped, graceful as a bird in the air, and then he plummeted into the river.