Charlie Holmes decides to go to London after discovering the secret of her origins. She also became angry with Georges, her grandfather who, to protect her, hid an important part of her past from her. Samy accompanies her on her journey. During one of their visits, to the prestigious house of Sherlock Holmes, Charlie discovers at the bottom of a trunk, scared to death, Tracy, the daughter of a famous actress. She tells her that she is being threatened with death by an anonymous person. She has already lost a sister, who died at 18 under mysterious circumstances.

Charlie's grandfather George is in a coma after an attempted murder. The police station mobilizes to find the culprit, while Charlie is excluded from the investigation. But Charlie is determined to shed light on the matter, behind the backs of the brigade, always with the help of Samy. But she quickly discovers that everything incriminates her...