Pascual León, a retired 65-year-old man, starts an elaborate plan of revenge after being diagnosed with Alzheimer's. Meanwhile, Jimena Guerra, a policewoman, finds a mysterious message addressed to her at the crime scene.

Pascual recovers from a health problem and continues with the next stage of his plan. Meanwhile, Jimena Guerra makes new discoveries: it is the work of a serial killer and Asunción de la Sal seems to be a key piece in the investigation.

Pascual's Alzheimer's advances, so he decides to go to Asunción to speed up his plan. Jimena finds a key element for the investigation which could solve the mystery surrounding the crimes.

Pascual travels with Nuri to Asunción and continues with the murders, although the accumulated lies won't be easy to handle.