Sixteen-year-old Penny has moved with her mom and huge dog, Ollie, to live above a small-town pub owned by her aunt. It's a relief to start over in a place where no one knows her father is in prison.

It's summer, and the only person she knows is her nerdy cousin Simon. Soon she meets Simon's best friend, Brent, and Brent's twin sister, Tara, and their pug, Wolfgang.

When Ollie digs up a human bone in the backyard of the pub, police are called. It turns out the bone is over twenty years old. Who can the dead person be? Surely Aunt Stella can't be involved.

Penny and Simon decide to investigate. Together with Brent and Tara, they form The Crime Club. And before long they discover one thing: if you've killed before, you can kill again.