'What are we paying for?' he asked in a clear voice.

The guard looked back over his shoulder, a dangerous look on his face, then turned round to look at Ben. He licked his lips, and his right hand lightly touched the body of his AK-47 before he answered with a single word. 'Taxes.'

Ben was about to respond, when he heard his father interrupt. 'Just get back in the car, Ben,' he hissed. Another look at the face of the guard persuaded him that maybe his dad was right, and quickly the two of them got back inside and shut the doors behind them. Abele sped off.

Ben couldn't help feeling indignant at having been so blatantly stolen from, and at the same time he felt the heat of Abele's frequent glances in the smeared rear-view mirror. 'That wasn't taxes,' he burst out finally. 'Was it?'

Abele shrugged. 'I already told you, in the Congo the only man safe from voleurs is the man with no money.'

'But they were policemen, not robbers.'

'Then you should think yourself lucky, young Ben,' Abele intoned. 'If they were real' – he struggled with the English word – 'robbers, you would not have got away without being searched. And if they had found more money in your shoe…' He put two fingers to his head to indicate a gun before making a clicking sound with his tongue.

'Then why on earth did you tell us to hide the money away?' Ben's dad asked, unable to hide his anger.

Abele shrugged again. 'On this road,' he said, 'you are probably safe from that kind of robber.' He thought for a minute, before adding, 'In the daytime, at least.'

They drove on in silence.

Ben felt the sickness of uncertainty in the pit of his stomach. Maybe his mum had been right – maybe he really shouldn't have come. The idea of Dr Bel Kelland, world-famous environmental activist, trying to ban her son from travelling to Africa had seemed pretty out of character, but she'd been adamant. The Democratic Republic of Congo was one of the most unstable places on earth, she had fumed, and she had been shocked that Ben's dad – or 'your father' as she would always disapprovingly refer to him – had even suggested that he accompany him on his business trip to the region.

'It's just too dangerous, Ben,' she had told him.

'More dangerous than Adelaide?' Ben had replied archly. It had only been a matter of months since the two of them had been caught at the centre of the terrible fires that had swept across the Australian city. A couple of weeks of his longed-for summer holiday spent exploring an exciting part of Africa would seem like a walk in the park compared to that, surely. It would take his dad a week at the most to complete his business, and then they would be free to do as they pleased. Russell had even suggested taking a flight to the holiday resorts of Kenya, and Ben was certainly up for that.

'Don't be flippant, Ben,' his mother had chided sharply, before changing tack a little and appealing to his reason. 'Look, love, I'm not going to ban you from going, but just think about it carefully, OK?'

'OK, Mum.'

He'd been as good as his word, reading up on the country that used to be known as Zaire on the Foreign Office's website. It made for pretty alarming reading, and the list of vaccinations he had needed was as long as his punctured arm. Back in England, though, the warnings had just been words on paper; now Abele's words had highlighted the fact that these were not just idle fears: this strange land in the middle of Africa was clearly a very dangerous place.

Bel had eventually become resigned to Ben's decision to go, but she had still been full of instructions. 'Don't forget to take clean water with you wherever you go; and make sure you and your father take your malaria tablets – before you leave and after you come back. It's very important, Ben. People die of malaria, in their millions. Its incubation period is between seven days and a month – chances are you wouldn't even know you'd got it till you were back in England.'

Ben was snapped out of his reverie by the sound of his dad and Abele in conversation – or rather his dad talking enthusiastically, and Abele listening quietly. 'I'm a scientist,' Russell was saying in that slightly monotone voice that he always seemed to lapse into when he started explaining about his work. 'A chemist, actually. Specializing in minerals and ores. The company I work for is in the business of examining naturally occurring ores and evaluating whether they are of a good enough standard for mining. The company you work for, as I'm sure you know, is currently mining tin in the east of your country, and they believe they have hit upon a rich vein of Coltan.'

'I would not know about that,' Abele muttered. 'I just run errands for the boss men.'

'Ah, well, it's a very interesting substance, Coltan…'

Ben's attention wandered again. He had heard his dad expound about the value of Coltan more times than he could count since it had been confirmed that he would be accompanying him on this work trip. Columbite tantalite – used to create tantalum, the magic ingredient in almost any electrical item you care to name. Without Coltan, there would be no mobile phones, no computer chips, no PlayStations. It sold for $100 a pound, and anyone who mined it would be rich. The DRC was one of the major producers in the world.

'The mine is in a village in the east of the country called Udok. Are you familiar with it?'

'Of course.' Ben could have been mistaken, but as Abele spoke he was looking at him in the mirror. He could have sworn he saw a tightening of the eyes, a look that was half suspicion, half fear. 'I would not travel to Udok if it were up to me,' he muttered.

'Why on earth not?'

Abele paused. When he answered, it was without much conviction, as though he was not saying everything he was thinking. 'That part of the country is very dangerous,' he explained. 'Many voleurs… And anyway,' he continued with a certain reluctance, 'it is not wise to disturb the land like that. No good can come of such things.'

Ben was about to quiz him further when he felt the car suddenly slow down again. The road had led them to what seemed to be a slightly more built-up area – the outskirts of Kinshasa, he assumed. 'Not another checkpoint?' he asked.

Abele shook his head. 'I don't think so.'

'Then why is everyone slowing down?'

For a moment Abele didn't answer. When he did, it was curt. 'Over there,' he said, pointing to something on the side of the road.

Ben squinted his eyes. There was something lying there in a disjointed heap. It was only after several seconds had passed that he realized what it was.

A human body.

It was raggedly clothed: what material there was appeared to have been ripped to shreds. The limbs seemed to be cruelly out of position, pointing in different directions that were never naturally intended. The head was facing away from the road, a fact for which Ben was profoundly grateful. 'Why doesn't someone do something?' he whispered, craning his neck to look back at the body as the car passed it.

'What is there to do?' Abele replied simply.

'Well…' Ben stuttered, 'he should be taken away. Buried. His family should be told…'

Abele laughed gently, but there was no humour in that laugh. 'In my country,' he explained, 'if you approach that body, you take responsibility for it. Nobody wants that.'

'But you can't just leave him there.'

'He won't be left,' Abele said gruffly. 'The wild animals will see to that. He will be gone in three days. Maybe four.'

Ben didn't know what to say.

'You are shocked,' Abele continued. 'And so you should be. My poor country is a shocking place. You are not in your safe England now, Ben Tracey. Remember that.'

Ben glanced in the mirror to see Abele peering back at him, his sharp, bright eyes seeming to glow in his black face. It made Ben distinctly uncomfortable.