Anna, Bett and Carrie Quinlan were childhood singing stars, The Alphabet Sisters. As adults they haven't spoken for years, ever since Bett's finance left her for another sister. Now Lola, their larger-than-life grandmother, summons them home for her 80th birthday extravaganza and a surprise announcement - she wants them to revive their singing careers and stage a musical she has written. Rehearsals get underway, and family secrets begin to be shared and revealed. But just as the rifts begin to close, the Alphabet Sisters face a test they never imagined.