Donna (Meryl Streep), the owner of a run-down hotel on a Greek island, is preparing for the wedding of her daughter Sophie (Amanda Seyfried) with the help of two old friends. Meanwhile Sophie has been reading her mother’s old diaries and has discovered that she has three possible fathers (Pierce Brosnan, Colin Firth, Stellan Skarsgård). Without telling her mother she invites them all to the wedding.