1989年，迈克・奥唐纳（扎克·埃夫隆饰）依靠强悍的身体素质和过硬的技术在高中的篮球赛场打出了名堂，很多大学愿意用全额奖学金来招募他的加盟，就在大家对他寄予厚望之时，女友斯嘉丽（艾莉森·米勒饰）的一个消息改变了他的命运，因为她的怀孕让迈克放弃了一切，跟斯嘉丽双宿双栖，去过普通人的平凡生活

20年后，人到中年的迈克（马修·派瑞饰）事业不顺，妻子斯嘉丽（莱斯利・曼恩饰）也准备和他分手，在两个孩子的眼里他无疑就是个失败者，这个时候的迈克开始怀念高中时风光的时候了，他时常在考虑，如果让他重新选择，他会不会做出不同的决定，幸运的是，他竟然真的有了第二次机会，一位神秘的看门老人（布莱恩·道尔饰）让他重返17岁，只不过那是年轻的外表，可心态却仍然是30多岁，迈克非常兴奋地想要重塑辉煌，但实践起来却没有那么简单。

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.