Esther has worked as a clerk for an investigating judge for years. Now, she is enjoying a quiet retirement. But this is suddenly interrupted, when Esther is diagnosed with Alzheimer's. The shock brings to light a long-buried memory. She goes through her old records, compiles a list of criminals, and sets out to eliminate them one by one, transforming into a clumsy yet mysterious vigilante. While Esther is plotting her revenge before she forgets, a talented young cop, Célia, finds her life turned upside down. An unknown serial killer, who receives widespread attention, is leaving messages for her on the victims' bodies. Her investigation leads Célia back to the place where she grew up, where the darkest secret of her past is buried. Their destinies collide as Esther seeks to remember while Célia tries to forget.