It all begins when Wendy decides to throw an end-of-year party at home with her friends. Before she gets a chance to ask her parents, her unbearable little sister Maureen steals her idea and asks their parents first. Unfortunately, the parents will allow only one party!

Maureen and Wendy start a series of crazy challenges to decide which one of them will host the party. With sister against sister, there is going to be trouble!