Before her mother died, Shelby promised three things: to listen to her father, to love as much as possible, and to live without restraint. Those promises become harder to keep when Shelby's father joins the planning committee for the Princess Ball, an annual dance that ends with a ceremonial vow to live pure lives --- in other words, no "bad behavior," no breaking the rules, and definitely no sex.

Torn between Promises One and Three, Shelby makes a decision --- to exploit a loophole and lose her virginity before taking the vow. But somewhere between failed hookup attempts and helping her dad plan the ball, Shelby starts to understand what her mother really meant, what her father really needs, and who really has the right to her purity.