Cordelia hared across a rocking deck, scrambled down two ladders and up a staircase hanging in mid-air.

She could almost feel the deadly swish of the pirate queen’s blade, the chomp of the Sea Dragon’s jaws. If she was caught … But she couldn’t worry about that now: now was her chance to talk to Prudence!

She stumbled past the dining table, still covered with mess from breakfast, trying to remember the way back to the cabin where she had seen the curtain twitch.

Cordelia picked her way along a horizontal ladder, swung on a rope across a gap between decks and skidded on to a high platform.

There!

The cabin lay ahead: Prudence’s prison.

She glanced over her shoulder to check she was not being followed. The Troublemakers’ shouts had faded, and the jungle was still and green all around her.

Cordelia edged across the trembling web of vines that led to the prison door.

To her surprise, the door was not locked. She pushed it open slowly, hoping it wouldn’t creak.

The cabin was very dark. Cordelia could not see a thing.

‘Prudence?’ she whispered.

There was no reply. Prudence must be crouched somewhere in frightened silence.

‘I’m a friend,’ Cordelia said gently. ‘My name is Cordelia Hatmaker.’

Still no reply.

Cordelia felt her way into the room and bumped into something soft.

‘Oof! Sorry!’ she gasped. But the soft thing rustled like blankets, and she realized she had bumped against a bed.

‘Prudence, where are you?’ she called, pushing herself upright and blundering on through the dark room. ‘I’m here to rescue you! I’ve got a sort of plan!’

She felt cloth under her hand and pulled. The cabin flooded with light as a curtain drew back.

The word had been carved in huge, reckless letters across the wall. Like a threat.

Apart from a four-poster bed and a rocking chair, the cabin was empty. Prudence was not there. But earlier Cordelia had seen a twitch at the window and heard a girl’s voice. She must be somewhere close.

Cordelia threw the window open. ‘Prudence Oglethorne!’ she called across the treehouse. ‘Where are you?’

There was no reply except the laughing call of some wild bird.

Cordelia turned back to the room. On the wall opposite, she noticed scraps of paper pinned to the wall with inch-long thorns driven into the wood. On one scrap, a single word was scrawled:

Was this somebody else the Troublemakers planned to kidnap?

Beside a tattered map of London, riddled with more thorns, other names were scrawled. A list of victims?

Cordelia peered closer. Arcana, Celestial, Sargasso.

No – she realized with a jolt – these were names of famous London chocolate houses! Mariana was not a person but a chocolate house: a gilded parlour on Air Street. This must be the Troublemakers’ next plan: they were going to attack the chocolate houses!

‘What are you doing?’ a voice snarled.

Cordelia yelped and swung round.

A hulking, wild-haired figure stood in the doorway: Never. He lunged at her.

‘If Thorn finds you in here, even Shelly won’t be able to stop you getting thrown to the Sea Dragon!’ the pirate growled, dragging her to the door, before freezing. Someone was tramping along the treehouse, like thunder approaching.

‘Thorn’s coming!’ Never gasped.

He quickly shut the door and towed Cordelia across to the window. He pulled the curtains shut, hiding them, and pushed his craggy face close to Cordelia.

‘Don’t make a sound!’ he warned.

Cordelia’s heart pounded as she heard the door squeak open. The floorboards shook as the pirate queen stomped into the cabin. Muttered words sizzled through the air like bad spells.

Never edged towards the open window, beckoning Cordelia. She sidled towards him, careful not to disturb the curtains. He pressed a rough finger to his lips, widening his eyes in warning. Then he took Cordelia by the arms, lifted her on to the windowsill – and pushed.