Stop it, I ordered myself harshly. It was over between the two of you anyway. If you doubted it, then that should have been your tip-off – because if he was still in love with you, there’s no way he’d have let you go in there without telling you. None.

The thought of it really being over between us – of Alex not being in love with me any more – hurt far too much to dwell on. I’d put the file that I’d stolen under my jean jacket, buttoning it into place, and now, as we walked, its stiff cardboard jabbed against my ribcage. Focus on that, I told myself, not Alex. And absolutely not on what happened in the cathedral. The file; the sandals hurting my feet. Seb’s hand. Just focus on Seb’s hand – the firm grip of it; how warm and caring it feels – and not bodies, sprawled helpless and bloody across the cathedral floor. Not the young preacher, with half his head blown away and one eye staring up at the painted angels on the ceiling.

Definitely do not think about these things.

The sidewalk had become trash-ridden and more crowded with people now; the buildings to either side looked run-down and grimy. I could sense from Seb’s sudden reluctance that we were almost there, though his body language was as laid-back as ever. He let go of my hand and put his arm around my shoulders.

“You’re my girlfriend again, okay?” he said. “Don’t look around you too much, no matter what you see. They don’t like outsiders here. They think of them as prey.”

I nodded, my throat almost too dry to speak. “No matter what I see?”

We turned a corner and there was a marketplace ahead: a long, dingy street filled with lit stalls. I could see clothes for sale; jewellery and cellphones. Vendors were shouting at customers in Spanish, hawking their bargains. Seb’s expression as he took it all in was twisted with more bitterness than I’d ever seen on it.

“This is the place where you can buy things,” he explained shortly. “Drugs, weapons. The end of someone’s life. Just ignore anything you see.”

Entering Tepito was like ducking into a long, rustling tunnel, formed by the plastic awnings of the market stalls. They seemed to close in around us, just like the thudding rock music that was suddenly everywhere. There were stalls selling angel statues, angel key chains, angel T-shirts. DVDs of popular movies, lots with the titles misspelled. Racks of “designer” clothes with labels that were just as wrong. I glimpsed two men off to the side; one tucked something inside his jacket as money changed hands. White, flashing smiles.