Now Innocent’s smile faded. Rather than answer, he turned to Patience and said, ‘Our guests must be thirsty. Pass round the water.’

Caleb jerked his head back, annoyed to be ignored. For an awkward nanosecond I thought he might insist on an answer. But as Patience pulled bottles of mineral water from the cardboard box at her feet Xander cut in with, ‘How did you make the switch to safari guiding?’

Innocent’s face lit up. ‘It’s my passion,’ he said. ‘Ever since I was small I loved animals. Stray dogs, cats, chickens, even little mice.’

I felt bad about killing the rat, but didn’t say anything.

He went on. ‘My mother tore her hair out over the number of creatures I brought home.’

‘Very David Attenborough,’ said Amelia. ‘He’s a TV naturalist on –’ She cut out when I dug my elbow into her side.

‘Yes,’ said Innocent. To Caleb he continued, ‘Only one good thing came from the army for me. It was that I saw this beautiful country, the national parks, Virunga and so forth, the paradise of them. And also I saw the threat to it all, from bad and greedy men – desperate men. In time I will tell you how we resist them if you like.’ Turning back to Xander, he continued, ‘So the first thing I did when I escaped the army was to train as a ranger, using my skills to help protect the park and its animals. I did that for five years. Then, because I had learned to speak English, I could start with the tour guiding too. And now I do both, guiding and the ranger work. I help defend the parks and show them off. Because the more people who see what’s actually in the rainforest, the more people will fight to save it.’

Mum had done well in her choice of guide. The gentle heat in his voice as he made this speech was heartfelt. I’d already warmed to him. The fact that he’d put himself on the line as a soldier in defence both of his country and its wildlife made me like him even more.

If the lake crossing was a smooth, comfortable ride, the road more than made up for it. A streak of orange dirt weaving through the emerald greenery, it had for years, according to Innocent, been cut to shreds by tyres and rain, then baked hard by the sun, then shredded by rain and tyres again. The result was a rutted, soupy, jolty, bumpy mess. We were in the back of another pickup truck, bouncing all over the place. When I could, I watched the driver in the wing mirror. His eyes, still bloodshot, were slits of concentration as he wrestled with the steering wheel, which was covered in fur that might once have been white but was now the colour of the rat I had killed. For some reason, the man unnerved me.

We spent a night in a permanent camp on the edge of the reserve. Innocent was in one tent, Xander, Caleb and I shared another, while Amelia bunked with little Patience. I think she wanted to take the young girl under her wing, but given where we were I suspect Amelia had more relevant stuff to learn from Patience than the other way around. Hard rain fell in the small hours and the noise on the canvas woke me up. It sounded as if we were inside a drum. In the morning, after a breakfast of salted hard-boiled eggs and strangely sweet bread, Innocent introduced us to the porters he said would be hiking into the bush with us.