Pediatric Alex Beck (François Cluzet), still devastated by the savage murder of his wife Margot (Marie-Josée Croze) in the early days of their marriage eight years ago, receives an anonymous email.
When he clicks on the link he sees a woman's face standing in a crowd and being filmed in real time - Margot's face. Is she still alive? And why does she instruct him to 'tell no one'?