Seventeen-year-old Sunny has always been a little bit of a pushover. But when she's sent a picture of her boyfriend kissing another girl, she knows she's got to act. What follows is a mad 12-hour dash around London.

Along the way Sunny meets a whole host of characters she never dreamed she'd have anything in common with. As Sunny discovers, a whole range of people is willing to help a girl on a mission to get her romantic retribution.