20-year-old-bride-to-be Sophie Sheridan is preparing to marry her fiancé Sky, but she has a secret: she wants her father to walk her down the aisle. After reading her mother Donna Sheridan's old diary, Sophie discovers that three men from her mother's past, Sam Carmichael, Bill Anderson, and Harry Bright could be her father. She secretly invites all three to the wedding, hoping she'll recognize him. As the wedding date approaches, Sophie spends time with each man, each believing he could be her father, while Donna reconnects with her past and Sky senses Sophie's distraction.