Innato tells the story of Sara (Elena Anaya), a psychologist who has left behind a traumatic past as the daughter of Félix Garay (Imanol Arias), a serial killer once dubbed by the press as “the diesel killer.” Now, the idyllic life Sara has built with her husband Aitor (Roberto Álamo) and their teenage son Sebas (Teo Soler) begins to crumble when Félix is released from prison — just as a new wave of crimes appears to replicate the murders committed 25 years earlier. After hiding her past from her family for years, Sara must now work with the police to solve the new cases.