Outside, light struck like a camera flash. It was that time of day when the sun has total control, when it establishes itself so fierce and high in the sky that it’s inconceivable to imagine it ever being defeated by a weak curve of moon. I walked as slowly as I dared. The leaves of the cottonwood threw spots of dappled shade across the path. I was barely able to field Chavez’s questions – How were the children? Were they enjoying Arizona? Not too hot for them? – trying instead to think of a way to put off the inevitable moment when the workers would glance up and see me approaching with this stranger in his hated uniform of the Migra. I could picture it clearly. The indecision in their eyes. Both Duval and Benjamín gone and far longer than they should have been. Their trust of me, a white woman, tentative at best. What if they didn’t hold their nerve? What if they dropped their tools and bolted for cover? The noise of hammering and sawing echoed closer and closer, and out of sheer desperation I bent down to tie my shoelace, and that’s when I saw it – somewhere in my peripheral vision – the waxy yellow flower of the whipple cholla. ‘Watch out for it,’ I heard Duval’s warning. ‘Ask Benjamín about his various spats with the cholla.’

Chavez stopped beside me. ‘Those shoes are no good in the desert. You must buy boots. I will take you to a good place in Nogales.’ I mumbled something and made to stand up, then executed what must have looked like the most pantomime of stumbles: avoiding Chavez’s hastily outstretched hand, I squeezed my eyes shut and threw myself into the barbed embrace of one of Benjamín’s so-called annoying small-town gangsters.

‘Mummy,’ Emmy moans from the back seat of the truck, ‘I’m bored.’

I open my eyes. My arm had been a pincushion. Several of the cactus spikes had also impaled themselves through the soft half moon of flesh between thumb and forefinger.

‘Don’t touch them!’ Chavez said at once. ‘You mustn’t leave the tips in.’ And taking me by the elbow, he helped me to my feet. ‘We must get you to the doctor.’ But as he’d said it, he’d directed a long hard look at the town over my shoulder.

‘How’s your arm?’ Chavez asks now, as if on cue.

‘My arm?’ I pull up my shirt sleeve. ‘Oh, it’s fine.’ The cactus spikes show up as a smattering of red dots, like a minor outbreak of chicken pox.

In the medical centre, the cute doctor had pulled out the sturdiest barbs with a pair of tweezers then reached into the cupboard behind him for a bottle of Elmer’s glue.