Rachel (Ginnifer Goodwin) is a talented attorney at a top New York law firm, a generous and loyal friend, and, unhappily, still single—as her engaged best friend Darcy (Kate Hudson) is constantly reminding her. But after celebrating her 30th birthday, perpetual good girl Rachel unexpectedly ends up in the arms of the guy she's had a crush on since law school, Dex (Colin Egglesfield)... who just happens to be Darcy's fiancé. As one thing leads to another in the frantic weeks leading up to Darcy's wedding, Rachel finds herself in an impossible situation, caught between her treasured friendship with Darcy and the love of her life.