In 1989, Mike O'Donnell (Zac Efron) was a star athlete with a full college scholarship imminent. He seemingly had it all, when, right before the championship game, his girlfriend Scarlet (Allison Miller) informed him she was pregnant. In that moment, he made the decision to throw everything away (including basketball and a chance at a scholarship) and proposed to her.
Twenty years later, Mike's (Matthew Perry) life has come to a standstill. Scarlet (Leslie Mann) has separated from him, forcing him to move in with his geeky, but millionaire, best friend Ned Gold (Thomas Lennon), his job is going nowhere, and his kids Maggie (Michelle Trachtenberg) and Alex (Sterling Knight) want nothing to do with him. While paying a visit to Hayden High School to reminisce about the life he threw away, he encounters the mysterious janitor (Brian Doyle-Murray). On the way home, is magically transformed back into his 17-year old self.
