But when Aurelio pressed him — gently now, humbled — to explain what he meant, the story came out, and it was the story of an ordinary miracle, the kind that happens in poor neighborhoods all the time and is never written down anywhere.

His daughter, Joaquín said, had been drowning in her final year of school — good with her hands, quick, but lost in the mathematics that stood between her and the technical institute she dreamed of.

There was no money for a tutor; there was barely money for the bus.

And Santiago, sixteen then, had heard about it the way he heard about everything in that building, and had simply started coming by in the evenings, after his own long day, sitting at the Fuentes family’s small kitchen table and walking the girl through equations by the light of a single bulb.

He never asked for a peso.