The gang from American Pie is back again, and this time they are facing one of life's biggest milestones: marriage. Jim (Jason Biggs) and Michele (Alyson Hannigan) are engaged and must navigate the difficult waters of wedding preparation, inter-family arbitration, and still find time to write their vows! As if that weren’t enough, Stiffler (Seann William Scott) is determined to make time with Michele’s hot younger sister Cadence (January Jones), but he’ll have to vie for her attention against Paul (Eddie Kaye Thomas) in a hilarious reversal of roles. With the help of Jim's dad (Eugene Levy) and the love of their friends, it all comes together despite many obstacles.