Jenny Windell is a teenage girl who's fascinated with murder mysteries. So when she finds her estranged aunt, Jane Latour, dead she's excited to have a mystery of her own to solve, but worried she may be a suspect she flees the crime scene. On the run, she befriends Derek Fenton, the dashing younger brother of acclaimed crime writer Archibald Fenton, and persuades him to join her in her Sherlock Holmes like attempts to solve the crime. It's no problem for them to outsmart dim-witted Inspector Marigold and they even find time for romance to blossom.