‘Benjamín, what are you doing?’ I look at him, scared that the sun has already baked him dry of all lucid thought.

‘Toribio Romo,’ he intones. ‘Come to those in need.’ And this time I remember. Duval’s murdered cleric, the patron saint of lost migrants. Holy illegal alien smuggler.

‘We will go to the place only Duval knows. There is water there. Duval will find us there.’

‘What if he doesn’t hear?’

‘He will hear,’ Benjamín says, struggling to raise himself. ‘But now we must walk.’

I follow Benjamín. Foot after foot, eyes trained to the ground, watching for cactus, watching for snakes. My heart beats unnaturally fast, my head throbs in time with some imaginary clock which ticks by the seconds, the minutes, the hours. How long have we been out here? How long since the children left? How long can we walk without water? The blisters come quickly. At first I stop and take off my sneakers and stick the small strips of Band-aid onto the raw skin, but they keep rubbing off and after a while there seems little point in bothering.

Information runs through my head, jumbled, conflicting. People can survive for days without water – dehydration can kill in hours. You should walk at night when it’s cooler. Except at night the desert belongs to its creatures, scorpions and tarantulas the size of a man’s fist. The thorns of the ocotillo will tear through your flesh like razor wire. Inside cactus there is life-saving water. I have a flash of Nora’s Mexican leaning against the tree, his blackened lips and tongue lacerated by spikes. I see Emmy’s pale face in the back of the car, speeding further and further away. Is it possible that my children are asleep in the vacuum-packed safety of their aeroplane? Is it possible that elsewhere in the world life could really be that normal?

The time passes, the heat intensifies. We walk, we rest, we walk again but nothing ever gets any closer. The mountains taunt us in the distance. Behind us the desert stretches out, infinite and unchanging. My throat is dry. It feels as though something is caught in my windpipe. I try to swallow but it gets harder and harder. Every so often Benjamín fiddles with the radio and I whisper along with him. ‘Santo Toribio Romo. Hear our prayer. ¡Ayúdenos!’ Once in a while he turns and I’m comforted to see his face, so achingly familiar to me now. He peers at me questioningly and I reassure him with a smile but it hurts to talk, so we don’t do it very much and soon it hurts to blink. I rub at the grit in my eyes then I realize there is no grit in them, they’re just dry, out of moisture, out of tears.