18-year-old Sophie Sheridan has a problem. It's almost her wedding day and she doesn't know who her father is. It could be any of her mother Donna's (Meryl Streep) past suitors: Sam Carmichael (Pierce Brosnan), Bill Austin (Stellan Skarsgård), or Harry Bright (Colin Firth). The only way for her to find out is to invite all three to her wedding to see what happens.