Sophie Sheridan, a bride-to-be, wants to find her real father in order to have him walk her down the aisle. With the help of her mother's diary, she discovers three potential fathers and invites them to her wedding without her mother and fiancé knowing. Chaos ensues as the three men arrive and Sophie tries to keep their presence a secret. Meanwhile, her mother Donna is faced with her past and the memories of her relationships with the three men. In the end, Sophie decides to ask Donna to give her away at the wedding, bringing the story full circle of love, family, and music.

Five years after the events of Mamma Mia! (2008), Sophie prepares for the grand reopening of the Hotel Bella Donna as she learns more about her mother's past. Along the way, she discovers Donna's young life and experiences the fun she had with the three possible dads of Sophie. As Sophie reflects on her mother's journey, she realizes that she is more like her mother than she ever realized before.

The third installment in the Mamma Mia franchise.