Fifteen-year-old Calli has just about everything she could want in life--two loving moms, a good-looking boyfriend, and a best friend who has always been there for support. An only child, Calli is excited when her parents announce that they want to be foster parents. Unfortunately, being a foster sister to Cherish is not at all what Calli expected. First Cherish steals Calli's boyfriend, then begins to pit Calli's moms against one another, and she even steals Calli's iPod. Tired of being pushed around and determined to get even, Calli steals one of Cherish's necklaces. But this plan for revenge goes horribly awry, and Cherish ends up in juvenile detention.

Isolating herself from her moms, her boyfriend, and even her best friend, Calli wrestles with her guilt and tries to figure out a way to undo the damage she's caused. When her moms are asked to take on another foster child, Calli sees an opportunity to make amends for her past mistakes.

Funny, moving, and emotionally rich, Calli is a portrait of an endearing young woman caught between adolescence and adulthood, striving to do the right thing even when all of her options seem wrong.