The two of them hurried silently through the forest until they reached the other end of the beach, then they dropped down onto their bellies and crawled the last few metres through the undergrowth, trying to ignore the thorns digging into their elbows and knees. The cage came into view as they parted the long grasses. It had been set right at the top of the beach, with its back pressing against the undergrowth. The man was still sitting against the bars and Amber winced as she saw that his hands had been lashed to the bamboo poles with twisted wire.

Alex inched to his left so that he was hidden directly behind the man, then he crawled out onto the narrow strip of sand at the back of the cage.

'Don't turn round,' he whispered. 'We're here to help.'

Instantly the woman in the cage jumped to her feet and began screaming out a torrent of French words. The little boy fell from her lap into the sand and began to cry with shock. The two men by the boat looked up.

'Be quiet!' hissed Alex, but the woman dropped to her knees, still shouting hysterically. Alex could only recognize one phrase. 'S'il vous plaît,' she kept repeating. 'Please, please…'

Suddenly, she thrust her arms through the bars and grabbed hold of Alex's hair. One of the pirates threw down his cigarette and started walking up the beach towards the cage.

'Let go!' said Alex, reaching up and trying to prise the woman's hands out of his hair. She would not loosen her grip. Then Amber thudded down onto the sand beside him. She started talking softly to the woman in fluent French. The woman stopped shouting and began to listen.

Alex twisted his head painfully to the side. The pirate was halfway up the beach now. Soon he would be close enough to see them clearly. Alex pulled his head back, tugging hard and, this time, the woman let go. Amber hissed one last, urgent sentence, then she and Alex crawled backwards into the bushes and lay flat and still, peering through the leaves.

In the cage, the woman turned and sat down beside her semi-conscious husband. She was trying to get control of herself but she was still sobbing loudly. The pirate walked right up to the cage and peered in with narrowed eyes. He looked at the sobbing woman, then began to walk round to the back of the cage. Alex tensed as he saw the twin crawl-tracks he and Amber had left behind in the sand. If the pirate saw those, they were in trouble.

Then the little girl stood up and spoke to the pirate. He stopped and looked down at her, trying to understand what she was saying. The little girl pointed to her mother, then acted out a mime. First her arm twisted through the air, imitating the sinuous movement of a snake. Then she became her mother, screaming and jumping about on the sand. Finally she imitated the snake again, moving the other way this time, back into the undergrowth.

The little girl smiled up at the pirate and shrugged her shoulders. He nodded his understanding, then gave the sobbing woman a disdainful look before turning away and heading back to the boat.

Alex slowly let out his breath.

'The little girl told him it was a snake,' whispered Amber, admiringly.

'Yeah, I gathered that,' said Alex softly. He peered out through the bushes. The pirate was back at the motor launch and lighting up another cigarette. In the cage, the woman had calmed down a lot. The noise had brought her husband round and he was sitting up, listening alertly as the little girl whispered into his ear.

'Ready for a second go?' asked Alex.

Amber nodded. Together, they wormed their way up to the back of the cage again and Amber began to talk.

TWENTY-THREE

'You were right, Li. They're hostages,' announced Amber as Paulo thrust a slice of mango and a coconut shell full of water into her hands. 'They're a French family. Philippe Larousse and his wife, Beatrice. The brave little kid is called Emilie and her baby brother is Robert. Philippe told me the pirates hijacked the yacht in the middle of the night and made the crew bring it here.'

'Where are the crew now?' asked Li. 'Still aboard the yacht?'

'No,' said Amber, reluctantly. 'The pirates tied them up and threw them into the bay this morning. The sharks got them.'

'But that is dreadful!' gasped Paulo.

'I told you,' said Li. 'There's nothing romantic about modern-day pirates. They're dangerous, greedy men.'

'They're keeping the family alive because they think they're worth a lot of money,' continued Amber. 'They're planning on demanding a huge ransom, but Philippe says the pirates are mistaken. He's a plastic surgeon, not a wealthy tycoon. The boat doesn't even belong to him; he only hired it for two weeks for a family holiday.'

'So what is going to happen to them?' asked Paulo.

'Philippe told me that the rest of the pirates went off in their own boat this morning. They took his passport and his business card with them. He thinks when the pirates find out he isn't a multi-millionaire, they will come back and kill him and his family.'

'Then we must rescue them!' said Paulo.

Alex had said nothing since they had arrived back at the temporary base in the rainforest. He had crouched silently on a fallen tree trunk, staring down at Hex and letting Amber tell the story. Now he spoke for the first time.

'Hex first,' he grated through clenched teeth.

Amber nodded and turned back to the others. 'There's a satellite phone on the yacht. And Philippe told me where his medical bag was.'

'Antibiotics?' said Li, hopefully.

'By the syringe-load,' said Amber.

Paulo grinned, then his grin faded. 'But how do we get out to the boat?'

'The motor launch is out, even if we could get past the guards. Philippe says the pirate leader took the keys with him this morning. There was a big argument about it, apparently. The leader doesn't trust his own men by the sound of it.' Amber shook her head. 'Somebody's going to have to swim out,' she said.

'I'll go,' said Alex, springing to this feet. 'I'll go now.'

'No,' said Amber, quietly. 'I'm going. I'm the best swimmer.'

Alex looked at Amber and nodded reluctantly. He knew she was right. 'How are you going to do it?' he said. 'There are sharks. And the pirates have rifles. If they spot you-'

In reply, Amber pulled a length of brightly coloured plastic tubing from the pocket of her shorts and held it up. 'It's from Emilie's toy giraffe,' she explained. 'I thought it would make a good snorkel. If I swim under the water with strong, steady strokes, I could probably make it to the boat without the pirates seeing me.'

Li nodded in agreement. 'You might fool the sharks too. It's weak, irregular splashing on the surface which attracts them. If you don't move like an injured fish, they might not be interested in you.'

'That's a comfort,' said Amber, with a wry grin.

'Maybe I should go,' said Alex, uncertainly. 'I made a promise to Hex. I should be doing something.'

'Like I said, I'm the best swimmer,' said Amber, calmly. 'And I know what to bring from the medical bag. And I know how to use a maritime satellite phone. Do you?'

Alex shook his head.

'Anyway, I want to do it,' added Amber softly, looking down at Hex on the stretcher. 'I know what it's like, needing drugs to keep you alive. Knowing you'll die without that next injection.'

She looked up at Alex and they shared a long look.

'Thank you,' said Alex, finally.

Amber slipped out from behind the cover of the rock and slid into the clear water with hardly a ripple. Immediately, she dived deep and struck out for the yacht with steady strokes. She had stripped down to her bra and pants so there was no waterlogged clothing to hold her back as she arrowed through the water, kicking her bare feet in a steady rhythm. The plastic tube was tied around her neck with one of her boot laces. The other lace held a short but deadly-sharp bamboo spear in place against her outer thigh.