In a small town in Michigan, fifteen-year-old Sarah Cole is stuck spending the summer at her Aunt and Uncle's with her sister, Lacey. She's not happy with the situation until she befriends a girl named Jackie. The three girls stumble upon the ruthless murder of a reclusive neighborhood woman and what's worse? One of the officers investigating the crime believes the girls are responsible for her death.

Fearing that this officer will frame them for the murder, the girls organize their own detective squad. They become the Super Spies and start their own investigation. The Super Spies can't understand why anyone would want to murder the "Cat Lady" until they start digging into her past and discover a horrible crime that happened thirty years ago. They uncover a connection between the two crimes and attempt to bring this information to the police, only to be reprimanded for meddling in the investigation. Not only are the girls upset by the admonition, but they also struggle with the fact that their exuberant investigating could provide a legal loophole allowing the killer to go free. Frustrated by this turn of events, the Super Spies realize it's up to them to snare the Cat Lady killer.

Or die trying...