She Walks In Darkness is inspired by the largest undercover operation against ETA, which marked a turning point in the fight against terrorism in Spain. Set against the historical, political, and social backdrop of the 1990s and 2000s, the film tells the story of Amaia (Susana Abaitua), a young Civil Guard officer who spends more than a decade working undercover within the terrorist group, with the aim of locating the hideouts they had hidden in the south of France.

