PART 1
—If you’re going to cheat on me with your own brother’s wife, at least don’t be stupid enough to leave the evidence in your jacket pocket.
Ana Lucía Santillán said those words in a low voice, alone in the dining room of the enormous family home in Lomas de Chapultepec, holding a black blister pack with a blue capsule called “Titan Force.”
She was 30 and had been married for six years to Rodrigo Santillán, sales director at a medical technology company. From the outside, her life looked perfect: a three-story house, dinners in Polanco, vacations in Los Cabos. Inside that house, though, Ana Lucía had become a shadow of who she used to be.
For the past six months, Rodrigo had stopped touching her. He’d moved into his office under the excuse of a business merger and treated every question as an annoyance. Around the same time, Valeria, his brother Daniel’s wife, started showing up with new handbags, expensive jewelry, and clothes a civil engineer’s salary could barely afford.
Daniel was supervising nighttime construction on the Circuito Exterior Mexiquense highway, spending days away from home. His absence had built the perfect opening.
Ana Lucía had noticed lingering glances, suspiciously accidental touches, conversations that cut off the moment she walked into the kitchen. She never had proof.
Until that afternoon.
Rodrigo came home in a rush, showered, and locked himself in his office. When Ana Lucía went to grab her jacket for the dry cleaner, she found the capsule.
The question was brutal: who did he need it for if he hadn’t been near his own wife in six months?
That night Daniel would be working until dawn.
The pain turned into icy calm. Ana Lucía remembered a veterinary medication her father had left over from the ranch dogs. She knew it could trigger a severe reaction in a person. She didn’t think about the law or how irreversible the damage could be. She thought about six years of humiliation, and about Teresa, her mother-in-law, calling her an “ungrateful peasant” even while she was contributing to the family’s finances.
Without weighing the consequences, she swapped out the capsule’s contents and put it back in his pocket.
After dinner, Daniel kissed Valeria and left for the construction site. Rodrigo told Ana Lucía to go to bed early, since he’d be “working all night.”
At 12:07, she heard the office door, footsteps in the hallway, and Valeria’s bedroom door closing.
She lay motionless, staring at the ceiling.
Twenty minutes passed.
Then a heart-rending scream shook the house.
—Help me! Get him out of here!
A hoarse roar followed, then banging against the wall, furniture breaking.
Teresa came out in her nightgown, pale. They both ran toward Valeria’s room. The door was locked from the inside.
When they finally got it open, they found Rodrigo naked, convulsing among torn sheets, foam at his mouth. Valeria, half-dressed, was huddled behind a dresser.
Teresa looked at her son, then at her favorite daughter-in-law, and fainted in the doorway.
Ana Lucía called 911 in a broken voice and played the terrified wife as the sirens approached.
But Valeria looked up at her from the floor and whispered:
—Teresa already knew about us.
No one could have imagined what was about to happen.
