At 38, Gu Chenzhou is pressured by his wife, Tang Zhixia, into signing divorce papers. Disillusioned with middle age, he unexpectedly activates the Youthful Rebellion System, which makes him younger and stronger every time he completes a rebellious act. He takes his long-abandoned motorcycle for a ride, takes his son to a club to cure his lovesick obsession, rejects a marriage proposal worth tens of billions, and escapes an arranged marriage forced on him by a wealthy family. As his body returns to the age of 30, the truth gradually emerges: years ago, he mistook someone else for the girl who had written him a letter, and his ex-wife had actually impersonated her. When Gu Chenzhou rises to become chairman of a corporate group and his ex-wife kneels to beg him to reconcile, he leaves her with one sentence: Who says you can never be young again?