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, but he's also the man who breaks her heart. In the present day, Donna's pregnant daughter, Sophie, dreams of renovating a taverna while reuniting with her mother's old friends and boyfriends on the Greek island of Kalokairi.