'Once the oil starts coming out of the coconut meat and running off the edge of the stone here,' explained Alex, 'you collect it in this half-shell.'

'What's the point of that?' asked Amber, suspiciously. 'Are you sure you're not just finding stuff for me to do, to make me feel better?'

'Definitely not,' said Alex. 'We really do need as much oil as you can collect. It has lots of uses. We can smear it on and it'll protect our skin from the sun and keep the mosquitoes away. And if we mix it with wood ash, it turns into soap.'

'Cool,' said Amber, happily settling to her task.

By the end of the afternoon, the camp was finished. They had rigged up five shelters over the beds, each made from a frame of bamboo poles lashed together, with a thatch of banana leaves and palm fronds. There was even a little shelter over the woodpile for the campfire. Next to the fire, there were two simple, bamboo benches, again set under their own, thatched shelters.

They sat on the two benches, looking around the camp in quiet satisfaction. Two more crabs were cooking in the storage tin over the fire and Paulo had packed the top sections of three green bamboo canes with young bamboo shoots and leaned them over the fire. The lower sections were full of seawater, which was just coming to the boil.

'They will cook in the steam,' said Paulo. 'Beautiful. Like asparagus.'

'If Heather could see us now,' giggled Li, gazing around the camp, 'she wouldn't believe it!'

'We're nearly ready for the night,' said Alex. 'Just a couple more things to do.'

Carefully, he filled a coconut half-shell with boiled water and added potassium permanganate from his medical kit until the water turned deep pink. 'Antiseptic,' he explained. 'In the tropics, a wound'll get infected very easily. So, anyone with cuts, grazes, burns or mosquito bites, step forward.'

'Yeah, well that's all of us!' laughed Amber.

'OK, we'll start with you, Amber,' said Alex. 'It's even more important for diabetics to make sure a wound heals properly. And we need to check for chiggers, too, so everybody take your boots off.'

'What the hell are chiggers?' asked Hex.

'They're a type of flea,' explained Alex. 'Chigoes is the proper name for them. They attach themselves to the shafts of hairs on your skin, then they feed off you by injecting saliva under the skin then sucking-'

'OK,' said Amber, hastily, 'I get the idea.'

'If you don't winkle them out, the bite'll become infected.' Alex had removed his boots and socks and was checking his feet and ankles. He pointed to three red dots just above his ankle bone. 'There. Chiggers. If we had some vaseline, I could smear some on and suffocate them. As it is, I'll have to use a sterilized needle to dig them out.'

'OK. Now I'm really grossed out,' said Amber.

'Is everything on this island out to get us?' groaned Hex.

Alex grinned. 'Just keep your boots on during the day, wash your socks every night, and you should avoid getting too many of them.'

They took it in turn to bathe their scrapes and bites and remove any chiggers while the food cooked. Li gave Alex's raw wrist and head wound extra attention, but both wounds seemed to be healing well.

Next Alex produced a small pack of anti-malaria tablets. 'These are special,' he said. 'They're not like the ones they were doling out every day on the Phoenix . You only need to take one and you have protection against malaria for a month. I have just enough for one each.

'And finally,' said Alex, once they had taken the tablets, 'we have the coconut oil.' Carefully, he picked up the two half-shells that Amber had managed to collect and handed one to each bench. 'Smear it on any exposed flesh. The smoke from the fire'll keep some of the mosquitoes away, but this'll deter the rest.'

'Can't we do it after we eat?' asked Paulo, gazing longingly at the steaming bamboo tubes.

'Nope. This is important. It's something we need to do every night. If we don't keep clean in humid heat like this, we've had it.'

The food was wonderful. To drink, they had half coconuts full of fresh boiled water. Alex crumbled a salt tablet into it before he served it out, to make sure everyone replaced the salt they had lost through the hot, sweaty day. They finished off the meal with the pawpaw fruit which Amber and Li had brought back with them that morning. It tasted rather like a melon and the soft flesh was full of juice. Once the pawpaw had all disappeared, they sat back in a tired, companionable silence, staring into the fire as the sun began to set behind the mountain. After a few minutes, Amber got up quietly and headed down to the tide line, where she sat with her back to them.

'Is she all right?' Alex asked, looking at Li.

'I think she's gone to do her injection,' said Li. 'Best leave her to it.'

'Poor kid,' muttered Hex to himself. The others looked at him in surprise. 'What?' he demanded, scowling fiercely.

'How did her parents die?' asked Li, looking at Hex with frank curiosity.

'Plane crash,' he answered. 'Just over a year ago. It was a small, private plane, with just the two of them in it. Her dad was piloting. Amber was due to fly with them, but changed her mind at the last minute and stayed on with friends instead. One of the engines caught fire over the Alps, and the plane crashed into the side of a mountain.'

'Did they find the bodies?' asked Paulo.

'Yeah,' said Hex. 'Apparently, they were badly burned. From what I read, the authorities wouldn't let Amber see them.' He frowned. 'Maybe that's why she's having a hard time moving on. You know that twist of gold she wears around her neck? Shaped like a broken circle?'

'Yes,' said Alex. 'Does it have some special meaning?'

Hex hesitated. 'I think so,' he said. 'That's an Omega sign.'

'Omega?' asked Li.

'It's the last letter in the Greek alphabet. Omega. The End.'

'The end of what?' asked Paulo.

Hex rubbed his nose while he tried to think of the right words to explain. 'Remember, back on the Phoenix , she said she didn't want a new beginning? She said her parents were dead. The End. Remember?'

Hex looked around at the others and they all nodded. 'And have you noticed how the gold is all rough and unpolished, as though it was beaten into shape? I think that golden Omega sign was probably made by hammering her parents' wedding rings together. The End. Do you see what I'm getting at? Amber can't move on. She doesn't want to.'

'Ten out of ten, code boy,' said Amber, softly, making Hex jump. 'I forgot, you're pretty good at puzzles, aren't you?' She moved into the circle of firelight and sat down on the bench, giving Hex a cool stare.

'So, I guessed right?' asked Hex.

'Yeah,' said Amber. 'You guessed right, code boy. But there is one thing you're wrong about.'

'What's that?' asked Hex.

'Back on the Phoenix you accused me of thinking money fixes everything.' Amber held out the golden Omega sign so that it glittered dully in the firelight. She looked at Hex with eyes full of a deep sadness. 'So, you tell me, Hex. How does money fix this?'