Three women. One secret. A deadly hunt.

The Hammer Killer spreads panic in Galicia at the beginning of the 21st century. Two decades later, the daughter of his last victim, Inspector Lola Xallas, is tasked with investigating the murder of Catalan businessman Tony Torres in Barcelona.

There she meets Olvido, a journalist and the prime suspect, and begins a race in which the past returns masked amid betrayals, lies, and a deadly pursuit. With the sound of the whistle, Entroido begins, and the worst nightmares resurface to confront her with the truth.