Goodbye Mr. Loser – Unemployed amateur musician Xia Luo (夏洛, Shen Teng) attends the wedding of Qiu Ya (秋雅, Wang Zhi), his high school crush. He overdrinks, makes an inebriated declaration of love to Qiu Ya, and angers his wife Ma Dongmei (马冬梅, Ma Li), who publicly shames him for being a poor provider and husband.
After causing chaos as his wife pursues him through the wedding hall, Xia Luo locks himself into a bathroom at the wedding venue, flies into a rage of self-hatred and passes out, waking up in his teenage body in his middle-school classroom in 1997. After impulsively beating up his teacher, setting fire to the classroom, and kissing Qiu Ya, he jumps out a window to end the dream, but after waking up in hospital still in 1997, is forced to make the best of things.
Although Xia Luo appears his normal teenage self to everyone else in 1997, he retains all his memories of adult life, including around twenty years of as yet unwritten pop music – which he decides to present as his own work, to gain fame and to win the heart of Qiu Ya. Over the next twenty years he becomes a pop megastar in China, taking the place of other superstar singers from the original 1990s to 2000s timeline, including ‘ghostwriting’ famous TV themes for pop radio and duetting with Sarah Brightman at the 2008 Beijing Olympic opening ceremony in place of Liu Huan.
Having achieved all of his ambitions including marrying Qiu Ya, Xia Luo gradually realizes that he was destined to be with Ma Dongmei – after he abandoned her in middle school in the new timeline, she nevertheless defended him from bullies and troublemakers and was forced into a simple life in a small apartment, marrying one of Xia Luo’s kindly but slow-witted classmates from 1997.
Xia Luo makes a proposal to Ma Dongmei’s husband to trade away all he owns in exchange for his wife, but the frustrated husband punches him into unconsciousness and he wakes up in a hospital bed, where it is discovered he is dying from AIDS. Ma Dongmei sings a final purloined song to him in his hospital bed, revealing that it was always her favourite (even though he was serenading Qiu Ya with it in the classroom at the time).
At the moment of his death, Xia Luo is thrown back into the original timeline in the wedding venue bathroom where he realizes that Ma Dongmei is the true love of his life. He runs back into the room and embraces her, which he continues to do as they are both arrested and taken to the local police station. He resumes his normal life much as before but with a new devotion to Ma Dongmei.
The film contains many references to Chinese popular culture in the late 1990s and early 2000s, including cameo appearances and depictions of well-known pop stars of that era. Some celebrities appear as themselves (including Jay Chou as a talent show contestant who performed a song Xia Luo had allegedly written, in reality one that Xia Luo had plagiarized from him), whilst others are depicted through stand-ins (for instance, Miss Na, who talent-spots Xia Luo in the new 1997 timeline).