The UCO (Central Operative Unit of the Civil Guard) manages to arrest the main suspect in the crime, who in reality didn't know the victims at all. Despite the detainee's lack of cooperation, the Civil Guard continues its investigation. His past behavior, along with statements from people close to the victim, paints a picture of Isauro López as obsessed with Yalennys. Statements from a bank employee and an ex-convict with shady connections in the criminal underworld will shed new light on the case. Their testimonies will allow the pieces of the puzzle to begin to fall into place.

Yalennys Valero and Juan Manuel Mata, two young people who barely knew each other, were murdered with a gunshot to the head. But the pieces don't fit together. The Civil Guard takes over the investigation and focuses on Yalennys, a young Cuban woman who a year earlier had signed a document stating that, if anything happened to her, the person responsible would be her former lover, Isauro López Hidalgo, a wealthy Galician businessman.