They woke at first light and checked on Chung. He looked pale and sweaty, and yet was shivering.

Amazon put her hand on his head. ‘He’s running a fever. That bite must have become infected.’

‘They say a human has the dirtiest bite of any animal. Time for us to hit the high seas.’

They pushed the fragile little canoe out into the surf, on the ocean side of the atoll. There was only room for three coconuts, but they were sure that would be plenty for the short voyage. But almost immediately they found a more urgent use for the shells. The canoe, without the raised prow and stern, and lacking the extra planks that were used to build up the sides of the boat, shipped water at an alarming rate. Within five minutes, Amazon and Frazer were sitting in several centimetres of water.

‘OK,’ said Frazer, ‘we take it in turns to bail and paddle. You have the first turn with the coconut.’

So Frazer paddled and Amazon scooped, but it was a losing battle. Even though the waves were modest, the little craft just wasn’t seaworthy, and both Amazon and Frazer began to have that sinking feeling. Nevertheless, they crept steadily closer to Uva’avu. They were helped by favourable winds and currents, which drove them in roughly the right direction.

After half an hour, they changed roles. It was almost a disaster as Frazer thought that they should also change positions. Amazon, trying to crawl round him, set up a crazy wobble, and the canoe rocked from side to side, taking on more seawater with each dip.

Amazon, however, saved the day by jumping over the side and into the sea, and using her hands to steady things. Without her weight, the canoe sat a little higher, and Frazer quickly bailed out the water they’d shipped. He then helped Amazon back on board.

As he did, Amazon noticed his hands: they were scraped raw from the rough paddle he’d been using.

Frazer seemed to notice them for the first time as well. He took off the ragged remains of his T-shirt, tore it into strips and gave two of them to Amazon.

‘Wrap these round your hands,’ he said, and soon the paddling and bailing began again.

By now the sun was high, and beat down upon them mercilessly. They drained the milk from the second coconut, and then the third, and wished that there had been room on the canoe for more.

But worse things were about to happen than thirst. The coconut-fibre ropes binding the fractured spars of the outrigger just couldn’t cope with the sea swell. First the ropes became loose, and the spars buckled at the join. Frazer tried some on-the-go repairs, but it was useless, and soon, one after another, the three spars failed. Without the stability provided by the outrigger, the canoe began to rock viciously, lapping up more water. Amazon’s bailing just couldn’t keep up. The canoe was soon half full of water. The island was still at least a kilometre away.

But that was not the worst of it. A black fin cut the water away to the right-hand side of the canoe. It sank down again and came up on the right.

‘What can we do?’ said Amazon desperately.

‘Don’t worry,’ said Frazer bravely, ‘that’s only a tiddler. It won’t bother us. But grab the other paddle. Let’s go flat out before she sinks. We might make it.’

They didn’t.

Two minutes later, the water was almost up to the gunnels. The shark had disappeared for now, but they knew it would be back.

‘We’ll have to try to roll her to empty out the water,’ said Frazer.

Amazon nodded in reply, but her face was taut with fear. They both slipped into the water, and tried to roll the canoe all the way round. It was much tougher than Frazer had anticipated: eventually they succeeded, but it picked up as much water as it shed.

‘We’ve got to swim for it, Zonnie,’ said Frazer.

‘I can’t …’ gasped Amazon as she trod water.

‘We can do this, cuz,’ said Frazer, staring deep into her eyes. ‘Try to keep your stroke nice and steady. Thrashing around attracts the …’

He didn’t want to say the word, and Amazon didn’t need to hear it.

‘You go first,’ he said. ‘I’ll follow right behind you. Remember, nice steady strokes.’

Amazon was a good swimmer, and, as Frazer recommended, she kept up a rhythmical front crawl. But she hadn’t swum much in the open ocean, and she found it much more tiring than doing lengths in the pool. Every so often she would mistime a breath, and take in a mouthful of saltwater.

Of course it didn’t help that she was on the very edge of panic. It was fortunate for her that she did not see what Frazer could.