The sisters are each at a turning point -- Vanessa is feeling stifled in a stale marriage and career; Ellie is perpetually single but desperately wants marriage and motherhood; and baby sister Georgiana is a successful model but longs to do something more serious with her life. Seizing upon the idea of finding their long-lost grandmother, the women set out on a trip to Montana, where they hope not only to find their father's birth mother but also to rekindle their bonds of sisterhood and possibly even find their true selves.

But they have no idea of the consequences of their quest. If the sisters find Hattie and live to tell their story, everything Hattie has worked and dreamed for will be destroyed. Will she allow the sisters to uncover the family secret and escape alive?