Frustrated by police inaction, Amparo travels alone to Seville, where a stranger warns her to stay away and the killer prepares to strike again.

Amparo unravels a 30-year-old blackmail fiasco, revealing a darker side to the Expo. Joined by Richi and Robledo, she searches old archives for clues.

As the explosion harms an unintended victim, Richi and Amparo track down a key player from the Expo, while Robledo teams up with a forensic investigator.