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 Donna's past. In 1979 young Donna, Tanya and Rosie graduate from Oxford University, leaving Donna free to embark on a series of adventures throughout Europe. On her journeys, she makes the acquaintances of Harry, Bill and Sam -- the latter whom she falls in love with. However, he is also the man who breaks her heart.