The metal of the truck is scalding to touch and any hope of finding shade quickly fades. The temperature is higher in than out, but the bottle of water is there, loose in the corner, still half full. I grab it then crawl over the seats and feel around in the flatbed for the plastic tote – the one bought by the old Alice, a girl who had broken down with her children at night on a mountain road with no provisions and wrung her hands in horror. Now, I do not allow my hands to so much as shake as I separate the lid from the base. Inside lies salvation of sorts. No hats, no satellite phone, no sunscreen and no more water, but a snake-bite kit, two Powerbars, a flashlight, bandages, a box of Band-aids and half a dozen sachets of antiseptic.

I stuff half the provisions into pockets, knot everything else into the sleeves of my shirt and climb out of the truck. A half litre of water. I swill it round the bottle. It will not do. Doggedly, I cast around for a stick then lever up the bonnet. I no longer look at the workings of the engine as though it were some architectural model for the Pompidou centre. I know my spark plugs from my pistons. I know my alternators from radiators and radiators have water in them. I remove the cap and then I remember. Sailors go crazy from drinking salt water, those jail escapees hiding in the desert had died drinking anti-freeze from a car radiator. Anti-freeze in the desert. The irony strikes me, of course, but my sense of humour is not up to dwelling on it.

Benjamín is where I left him. He looks grey and near to death himself. I give him as much of the water as I dare and force the Powerbars down both our throats. This time he makes no protest as I undo his shirt and unravel the bandage. The wound has opened up and is oozing blood and pieces of liverish-looking clots. I press the squares of antiseptic wipes against it, wondering how Benjamín could have possibly found the strength to beat a man to death and praying he has kept enough in reserve to carry on, because sooner or later that’s what we will have to do. My shirt provides some shelter over our heads but the sun bores contemptuously through the thin cotton and after a while I give up and sit there, waiting for Benjamín to recover.