Seventeen-year old Bree, is ecstatic to discover that she has an identical twin sister. When she's told Cassie is coming to live with her, she knows they'll be best friends. After all, she's always wanted a sister.
Luke, Cassie's boyfriend, wants nothing more than to enjoy what's left of summer vacation with the girl he's loved forever. When her identical twin, Cassie, breezes into town and he can't tell them apart, he knows he's in for trouble.
Bree discovers that she and Cassie couldn't be more different. Cassie is wild and impulsive. She's from the big city and hates Bree's small town and everything in it, everything except Bree's boyfriend, Luke. When Cassie becomes obsessed with claiming Luke as her own, Bree learns how deceptive, ruthless, and frustrating sibling rivalry can be.