It's 1959 and a new killer haunts the streets of London branding roses on his victims. The police have turned to the Inquirers at Miss Brickett's for assistance and second year Marion Lane is assigned the case. But she's already dealing with her own mystery having received an unsigned letter warning her that one of the three new recruits should not be trusted. She dismisses it at first but her informer always seems to be one step ahead of her predicting events before they happen. When a fellow second-year Inquirer is murdered Marion must come face-to-face with her informer to find out everything they know. Until then no one at Miss Brickett's is safe and everyone is a suspect.