In 1989, Mike O'Donnell (played by Zac Efron) relied on his strong physical fitness and excellent skills in the high school basketball court. He has made a name for himself, and many universities are willing to recruit him with full scholarships. Just when everyone had high hopes for him, a message from his girlfriend Scarlett (Alison Miller) changed his fate, because Her pregnancy made Mike give up everything, live together with Scarlett, and live the ordinary life of ordinary people
Twenty years later, the middle-aged Mike (Matthew Perry) had a bad career, and his wife Scarlett (Matthew Perry) Leslie Mann) is also about to break up with him. In the eyes of the two children, he is undoubtedly a failure. At this time, Mike began to miss the glory days in high school. Will he make a different decision? Fortunately, he did have a second chance. A mysterious old janitor (Brian Doyle) let him return to 17 years old, only But that is a youthful appearance, but the mentality is still in the 30s. Mike is very excited to restore the glory, but it is not that simple in practice.