Grandpa… I’m so hot… please don’t leave me alone… my eight-year-old adopted granddaughter whispered to me at 2 a.m., while my son was celebrating his “real son” on a cruise… But what I found inside that house was something they never imagined I would see. “Your brother is our real son, just try not to get in the way this week.” That was the last thing Sofía, my eight-year-old adopted granddaughter, heard before my son Miguel and his wife Paola closed the door of their house in Querétaro to leave for a Caribbean cruise to celebrate Mateo’s birthday, their “blood miracle,” as Paola boasted on Facebook.

PART 1

“Your brother is our real son, just try not to get in the way this week.”

That was the last thing Sofia, my eight-year-old adopted granddaughter, heard before my son Miguel and his wife Paola closed the door of their house in Querétaro to leave for a Caribbean cruise to celebrate Mateo's birthday, their "blood miracle," as Paola boasted on Facebook.

I didn't know it then.

I found out at 2:04 in the morning, when my cell phone vibrated on the nightstand and I saw Sofia's name on the screen.

—Grandpa… I’m so hot… please don’t leave me alone…

Her voice was barely a whisper. She breathed with difficulty, as if every word hurt her.

—Where are your parents, my child?

He took a while to reply.

—They went on the cruise… Mom said that if I got sick I would ruin everything for Mateo… they left me medicine in the kitchen, but I get dizzy when I stand up.

I felt my chest close up.

—Are you alone in the house?

—Yes… but they told me not to bother the neighbors unless it was something serious.

I hung up only to call him back on speakerphone while I hurriedly got dressed. At seventy, I no longer drive at night, but that morning I crossed the city as if the devil were after me.

—Don't fall asleep, Sofi. I'm coming.

—I'm going to behave… I won't cough anymore… don't tell Mom I made any noise…

That phrase broke something inside me.

When I arrived at the gated community, the house seemed perfect: manicured lawn, warm lighting, a clean truck in the neighbor's garage. But when I opened it with the emergency key Miguel had given me years before, the air inside was heavy, hot, and suffocating.

They had turned off the air conditioning.

In the kitchen I found a cheap bottle of syrup, an empty glass, and a note written in Paola's handwriting:

“Sofia, don’t overreact. Take your medicine and go to sleep. Mateo deserves a quiet week. Don’t call anyone unless it’s a real emergency. Don’t ruin this trip.”

Next to the note was the digital thermometer.

It read 39.7 °C.

They had seen him.