THE ROOM WAS full of cages and sad smells. There were parrots, songbirds, lizards, spider monkeys, a tank of tropical fish – and Selkie, lying in a cage beside an old bathtub full of dirty seawater.

Nim raced across the room, yanked open the cage door and threw herself onto the sea lion, hugging and kissing her, rubbing her head and tickling her whiskers. Selkie whuffled and opened her eyes.

‘It’s okay, Selkie,’ Nim whispered. ‘I’ve come to—’ but before she could finish the sentence, a deep voice snarled, ‘Hey! What are you doing here?’

Nim looked up at a tall pale man with steel blue eyes. Nim didn’t recognise him, but Jack would have, and so would Alex. The Professor had been on the Troppo Tourist boat that scared Nim’s mother’s whale to the bottom of the sea, and on the one that had dropped off Alex and her tiny boat in the terrible storm when Jack was lost at sea and Alex came to rescue Nim.

All Nim knew was that he was the person who’d seal-napped Selkie. She was as angry as Fire Mountain before it erupted.

But she also knew she’d never get Selkie out of here if she let that fire escape.

‘Are you the Professor?’ she asked.

He nodded. ‘How did you get down here?’

‘I want to work with the animals,’ said Nim.

The Professor laughed. ‘Let me guess: your mum’s on the crew, she smuggled you on board, and now you’re bored!’

Nim nodded as if he’d guessed her secret.

‘What’s your mum’s name?’

‘Alex,’ said Nim, and then she felt even worse. Her mother’s name had been Joni.

‘And will she think it’s a good idea for you to be snooping around down here?’

‘She knows I like learning about animals,’ Nim said quickly. ‘And … and I thought you’d like to see this marine iguana.’ Fred stared fiercely.

‘That,’ said the Professor, ‘is the ugliest thing I’ve ever seen. Luckily, some people like ugly. Find an empty cage and stick it in.’

Fred tucked himself tighter around Nim’s neck.

‘HE’S NOT GOING IN A CAGE!’ Nim said. ‘Animals don’t belong in cages!’

The Professor’s voice was like ice. ‘The Foundation for Research into Intelligent, Unique and Interesting Animals helps animals from all over the world. The most intelligent, unique or interesting will go to millionaires’ homes – I mean, be relocated in appropriate environments – at the end of the cruise.’

‘But … the iguana could learn to be even more intelligent, unique and interesting if he stays with me!’

The Professor shrugged. ‘Suit yourself – as long as you remember that all the animals on this ship are the property of the Foundation. But if you want to tame him, I guess I can allow that.’

‘We’ve already put on a show for the Kids’ Klub.’

He laughed, a thin sort of laugh. ‘So you fancy yourself a mini-Professor, do you? Think you could take over my job of giving animal lectures to the passengers?’

‘No, no, of course not! It was just a little show for the kids. But I could help you … I’ve even worked with sea lions before. I bet I could teach that one all sorts of tricks!’

‘That sea lion,’ the Professor said, ‘is a mean, vicious beast. It tried to bite me when I rescued it. It’ll be more cooperative after a few days with no food.’

Nim felt as if someone had thrown a coconut hard against her stomach. She took a deep breath. ‘Think, think!’ she told herself. ‘All that matters is helping Selkie!’

‘Sea Lion,’ she announced to the cage, ‘your name is … Selkie! Selkie, come out!’

‘You can’t do that!’ the Professor bellowed as he jumped out of Selkie’s way.

‘Selkie,’ Nim began.

The Professor grabbed a long whip from the corner of the room.

Nim looked around wildly. There was nowhere to hide. ‘Don’t you hit her!’ she screamed, and leapt in front of her friend.

‘We’ll get out of this somehow,’ she whispered to Selkie. ‘Just do what I say, even if it seems stupid.’

‘Get away from her,’ the Professor snarled.

Nim ignored him. ‘Selkie: handstand!’

Selkie raised herself on her front flippers, and did her best handstand.

What next? Nim thought, desperately.

Fred scurried across to Selkie. He rolled himself into a ball.

‘Oh, Fred!’ said Nim.

Fred rolled himself tighter.

‘Selkie,’ said Nim. ‘Soccer!’

Selkie sat thinking with her head on one side, the way she did when something was tricky. Nim always shouted at her when she threw Fred instead of the coconut when they played soccer, and Fred always sulked.

‘Soccer!’ Nim said again.

Selkie flicked Fred up with her nose, and threw him neatly to Nim. He climbed tight around Nim’s neck again.

‘Thank you!’ said Nim. ‘Now, give me a kiss.’

Selkie waddled over and whiskery-kissed Nim on the cheek.

The Professor’s eyes opened wide with surprise. He smiled as he put down his whip. ‘Okay, girlie, you can help.’