A golden summer, and six talented teenagers are looking forward to the brightest of futures - until a daredevil game goes horribly wrong, leaving three strangers dead. 18-year-old Megan takes the blame for the crime, leaving her friends to get on with their lives. In return, they each agree to a 'favour', payable on her release from prison. Twenty years later Megan is free. It is payback time. And her friends start disappearing, one by one . . .