By the time morning came, his head felt stuffy and his eyes were tight with tiredness, but he was glad to see the steely grey of dawn lighten up the room little by little. He examined his skin for the telltale red welts of the insect bites that he suspected he would be covered with, but the mosquito net appeared to have done its job. Nevertheless, he gratefully gulped down that morning's dose of Lariam, the anti-malaria medication he had been prescribed. As he did so, he remembered with a grim smile the warning the doctor had given him: that the medicine could have certain side effects – dizziness, nausea, even paranoia. He wondered if the uncomfortable feeling he had about this place was down to the drugs. Somehow he didn't think so.

His dad had explained over supper the previous night that today he would be going to the mine with Suliman, the mine manager. Ben was to stay in the village, where Abele would look after him. Ben hadn't argued – the mine didn't hold much interest for him, and he had too many unanswered questions about what was going on round here to be diverted by his dad's dry experiments and sample-taking.

At seven-thirty exactly, Suliman arrived in an old Land Rover. Flanked by two men who said nothing and lurked at the entrance to the compound, he approached Ben's dad with an outstretched hand and flashed a smile at Ben himself. Any hint of the suspicion he had demonstrated towards Ben the previous day seemed to have disappeared, although he did not seem to want to catch his eye more often than necessary. 'We need to get started, Mr Tracey,' he rasped at Russell. 'There is a lot to get through.'

Russell nodded, then walked over to give Ben a kiss. Ben knew the signs and offered him his hand instead, which his dad shook a little awkwardly. 'Abele should be here soon,' Russell said. 'I'll be back as quickly as I can.'

Ben watched from the entrance to the compound as Suliman ushered his dad into the waiting jeep. It made a deep, throttling sound as it started off, then disappeared, leaving a cloud of dust and an imprint of the tyres in its wake. Ben waited for it to go out of sight, then stood there for a little longer watching the business of the villagers milling about the square. There were more of them this morning than there had been the previous night, but they still walked with that abrupt haste, none of them stopping to speak to their neighbours. It was half an hour before Abele arrived, a loaf of bread in his hands. They greeted each other wordlessly before walking into the compound and sitting down to share the bread in rough hunks. It was hard and tasteless, but Ben was hungry.

'We should stay here today.' Abele broke his silence once he had finished eating.

Ben shook his head. 'Why?'

Abele put his hand out, palm facing upwards. 'The air is thick,' he explained. 'There will be rain soon, and heavy.'

'So what? The worst that can happen is we'll get wet.' Ben smiled as he thought back to the events in London only a few months previously. 'It's only a bit of water.'

Abele looked at him severely. 'When it rains, it will be fierce. You will need to find shelter.'

'All right, all right,' Ben told him a bit indulgently. 'I won't go far, and if it rains I'll come straight back. But I'm definitely going out – you stay here if you want to.'

Abele settled himself more comfortably on his sawn-off tree trunk to indicate that that was precisely what he intended to do. Ben shrugged, rubbed the crumbs off his lap, and wandered out into the main square.

Remembering the advice he had read on the Internet, the first thing he wanted to do was buy drinking water; it would be foolish to assume that his system would easily assimilate the local water like the villagers themselves. He looked around to try and find someone he could ask, but everyone seemed to be avoiding his gaze; if he did catch anyone looking at him, they would jerk their heads down to the ground almost immediately. After a minute or two, a couple of young children came running towards him, shouting words he could not understand; he tried to ask them in slow, simple English where he could buy bottles of water, but they clearly did not know what he was talking about and carried on shouting at him.

But then, from the corner of his eye, he saw a figure he recognized at the other side of the square. It was Halima, dressed identically to the way she had been the previous day. Trying to ignore the children clutching at his legs, he waved at her, his right arm forming a large arc in the air. Halima appeared not to notice him, keeping her eyes resolutely in front of her, so to attract her attention he shouted her name. 'Halima!' he called. 'Over here!'

As soon as he did so, Ben felt self-conscious. Everyone in the square turned momentarily to look at him before going back to what they were doing. Halima did the same, but unlike all the others she kept her eyes on him a little longer. Her face scrunched up into what looked to Ben like a gesture of warning, and she shook her head sharply before turning and walking out of the square.

Ben watched her leave, perplexed by her actions. She had seemed so eager to speak to him yesterday – what had caused her to walk away like that now? Still trying to work this out, he strode purposefully away from the children at his feet, a frown on his face, keeping a lookout for somewhere he could buy water.

On the other side of the square there was a hut with a few old red crates outside. Ben approached to see that they held unmarked bottles with silvery metal lids. Most of them contained what looked like water; a few seemed to be filled with cola, others with a milky liquid he couldn't identify. He helped himself to two bottles of water, then walked inside, pulling a note out of his pocket as he did so.

It took his eyes a few moments to get used to the darkness inside. When he did so, he saw an old woman, her skin dry and wrinkled, staring unsmilingly at him. She sat on a high wooden stool, surrounded by other bottle crates, though these were uniformly empty. Ben held up the bottles to indicate that he wanted to buy them, then thrust the note towards her. Her hand lashed out more quickly than her frailty would have suggested it could, and she stuffed it into a pouch tied round her waist, pulling out a few coins change and handing them to Ben in return. As she did so, however, there was a sudden commotion at the door. Ben spun round to see another woman standing in the doorway, a water bottle in her hand. The shopkeeper spat some harsh words at her in Lingala, which the woman responded to equally harshly, and a loud argument followed, with Ben standing somewhat perplexed in the middle of it. The shopkeeper jumped from her stool with surprising agility and snatched the bottle back from her surprised customer, the two of them shouting at each other all the while.

Amidst all the confusion, Ben heard a voice. It was Abele, standing just outside the hut, calling to Ben to come out. Skirting round the edge of the ongoing argument, he slipped outside. 'Blimey.' He smiled at Abele. 'What was all that about?'

Abele's face remained severe. 'The woman owes the shopkeeper money. She wants to take more water, but the shopkeeper will not let her until she pays her bills. The woman is saying that her husband is very sick. He needs clean water or he will die.'

Ben listened in horror to what Abele was saying. 'You mean they can't get clean water without paying for it?'

Abele shrugged. 'There is a tap in the village, but the water there is not always the cleanest.' As he spoke, the woman stormed out of the shop, past the two of them, and off towards the centre of the square. Ben ran after her. 'Excuse me!' he shouted. The woman turned, the surprise of seeing this young white boy calling her evident in her face. As he approached, Ben held out one of the bottles of water he had bought. 'Take it,' he said, thrusting it into her hands.