And so it was that Amazon Hunt came to believe that she was dying.

‘I’m not moving,’ she groaned. ‘Not ever again.’

It was the following day. Amazon had missed the evening meal, although the mysterious Leopold Chung was also absent. Nor had she made it for breakfast. Or lunch.

‘You’re getting up, and that’s it,’ said Frazer. ‘I’ve got the perfect cure for seasickness.’

‘If it’s something I’m supposed to eat or drink, forget it. I can’t even keep my own spit down. My mouth tastes like I slept with your socks in it.’

‘Nice! No eating or drinking involved, I promise. It’s something my dad taught me. And he said your dad invented it.’

Amazon’s curiosity was piqued.

‘OK, what is it?’

‘Fish baseball.’

‘Fish baseball …? Are you making this up?’

‘Me? Make stuff up?’ grinned Frazer.

Amazon permitted herself a small, thin-lipped smile in response.

‘How do you play this stupid game?’

‘Come up on deck and I’ll show you.’

Ten minutes later, Amazon, her face washed, her hair and teeth brushed, but her stomach still feeling as though it were full of live giant eels, pushed her way through the hatch and up on to the deck. The sky was a thousand shades of grey, and the sea was dark and troubled, but at least it wasn’t raining.

There were half a dozen members of the Tian-long’s crew on deck. Some were involved in unfathomable nautical activities involving ropes and pulleys; others sat or stood smoking cigarettes. None of them looked particularly friendly; but nor did they glower quite so fiercely as Matahi, who was also on deck. He was sitting with his back to the middle of the three masts, carving away at what looked to Amazon like the giant tooth of a sperm whale, which appeared to be his only possession, apart from his clothes. He did not even look up as they came on deck.

Amazon gulped and staggered, and had to hold on to the same mast to support her wobbly sea legs. Matahi muttered and shuffled round the mast to avoid her.

‘See, you’re feeling better already, aren’t you?’ said Frazer cheerfully.

Amazon noticed he was wearing a big baseball mitt.

‘You know,’ she said, doing her best to keep the eels from spilling out on the deck, ‘that in England we play cricket, which is like baseball except you need a brain, and anyone who used a great big glove like that to help catch the ball would be considered a sissy, and get hidden down at third man or fine leg.’

‘I really didn’t understand a word of that, cuz, and I assume you were doing your English sarcasm thing. But I really don’t mind. You’re sick and I’m the doctor. Now –’

Frazer was about to explain the rules of fish baseball, but he didn’t have to. Partly because the rules of fish baseball are really very simple, and partly because he was able to give a practical demonstration, which is, of course, always the best way to learn a new game. For at that moment a flying fish fizzed through the air, right in between Frazer and Amazon. Frazer threw out his gloved hand and it smacked into the baseball mitt.

It was all so totally unexpected that Amazon cried out in delight. A couple of the crew had seen what had happened and they cheered and clapped, and shouted congratulations in Cantonese.

‘How … what …?’ stammered Amazon.

Frazer was almost as astonished as his cousin, and stared dumbfounded at the stunned fish, caught in the webbing of the mitt.

He had been up on deck earlier and had seen the flying fish gliding over the waves. A couple of them flew right across the deck of the Tian-long, and it was then that Frazer had vaguely recalled what his father had told him about the game he had played as a boy. Each of the cabins was done out in a theme and, by a brilliant stroke of luck, Frazer’s was baseball – there were posters of long-dead stars, along with a bat and an old sweat-darkened mitt, its leather cracked and crumbling.

Frazer was bored half to death. Bluey was busy writing up scientific notes for his PhD thesis, and the taciturn Matahi was about as much fun as a slap in the face with a wet fish. But catching fish – literally catching them – that had to help pass the time, didn’t it?

So down he had gone to fetch his cousin, even though he thought fish baseball would probably never work – he even suspected that it might all have been a joke dreamed up by his dad. But then suddenly he had seen the flash of light on the scales, and here it was in his mitt. This definitely counted as one of those little moments of perfect joy.

Together Amazon and Frazer looked at the flying fish. It was about fifteen centimetres long, and a lovely iridescence played along its shining silver scales; but the truly amazing thing about it was the enormous pectoral fins, just behind its gills. They were a pale pink colour.

‘They’re like a swallow’s wings,’ said Amazon. ‘Even so, I’m amazed it can get this high – the deck must be three metres above the water …’

‘Yeah, these guys are actually pretty good fliers. They can glide for four hundred metres or more if the wind’s right. It’s how they escape from predators.’

‘So is something chasing them?’

‘Yep, must be. They don’t just fly for fun. Dolphins or tuna, maybe.’

Flying fish were interesting, but dolphins were quite another matter.

‘Dolphins!’ Amazon squealed. ‘I’ve never seen a dolphin. Where are they? I want to see them now!’

Suddenly she didn’t feel at all seasick. Frazer’s idea was working better than even he had hoped.

‘Sure. I must have seen a hundred while you’ve been rotting in bed.’

‘WHY DIDN’T YOU TELL ME!’ yelled Amazon.

She ran to the side of the boat and leaned out, straining to catch a glimpse of the dolphins.

‘Wait, put this on,’ said Frazer, trailing after her with a life jacket. ‘If Bluey comes up and sees I’ve let you flit about the place without a life vest on, he’ll tell my dad and then I’ll be grounded for literally the rest of my life. And unless you plan on eating him we should throw this little one back in the drink, as well.’

Amazon tutted at having to wear the jacket, but saw the sense in it: the ship carved its way gracefully through the waves, but this wasn’t some huge liner or ferry that chugged along on straight lines: it rose and fell and swooped and swayed like a living thing. She was wrestling with the life jacket when another fish zipped across the deck. It was out of reach, but Amazon yelped again with excitement.

‘OK, my turn with the mitt!’ she said and forced Frazer to hand it over.

Several of the crew had gathered round to watch. Only the aloof Polynesian took no notice. He sat and carved his whale tooth as if he were alone in the world, or blind to it.

Two more flying fish sailed over the deck, but both were way out of reach. Amazon’s efforts were greeted with more good-humoured cheering from the crew.

‘This is impossible,’ said Amazon, laughing.

‘Well, I did it,’ Frazer replied smugly.

‘That was just a fluke. It flew right into your glove. In fact, it wouldn’t surprise me if you’d bribed it.’

And then one of the flying fish thwacked into the back of Amazon’s head with the force of a heavy punch. She staggered forward and hit the low rail round the edge of the ship. She almost fell, then half recovered her balance, her arms windmilling, but then the ship, caught by the biggest wave yet, rolled sharply.

Had she not been stunned by the fish, Amazon would probably have kept her footing, but as it was, it was the turn of the thirteen-year-old English girl to fly. And, as she fell, she screamed. She wasn’t screaming merely because she was falling overboard from a sailing ship in the middle of the world’s biggest and most dangerous ocean. And it wasn’t even the fact that her life jacket, still unfastened, had fallen off uselessly behind her.

No: she was screaming because as she plunged downwards she caught a sudden, nightmarish vision of what it was that was hunting the flying fish.

Not dolphins.

Not tuna.

Not even sharks, although they would have been frightening enough.

This was something infinitely stranger and more nightmarish than any mere fish. These creatures were about the same size as Amazon, and coloured a vivid red. Their long, tubular bodies were flanked with undulating wings that propelled the beasts through the water at startling speed. Towards the end of each tube, two huge eyes goggled, restlessly scouring the water for prey. And ahead of the body stretched a ring of tentacles, armed with teeth that were curved like the talons of an eagle.

Amazon could see them surging under the water, like smart torpedoes, each rush sending another little group of the flying fish soaring into the air.

It would all have been fascinating were it not for the awkward fact that she was about to plunge in beside them.

As she fell, she was also vaguely aware of a flurry of motion behind her on the boat. Frazer, she thought, making a desperate and futile lunge for her. Or perhaps one of the crew …

But they were all too late, too far away. The only thing that was going to save her from drowning in the cold, grey sea was that she was first going to be torn apart by these unearthly predators.

So yes, she screamed.

And then there was a terrific jolt, just before she hit the water. The wind was knocked out of her, and a second later came the shock of the cold seawater. But she also felt something gripping her. Something hugely strong. It was two brown arms.

‘Do not struggle, little sister,’ came the voice of Matahi. ‘You are safe.’

And all around her the sea boiled with frantic flying fish, and thrashing squid in the midst of a grim battle for survival.