Huang Yu-xuan lost her boyfriend from a plane incident two years ago. She misses him a lot and sends messages with no reply. Meanwhile, her colleague claims there is an app that can find someone who looks identical to you.
Huang Yu-Xuan is shocked to find out that her boyfriend was planning to propose to her. Meanwhile, through Ah-Tuo's app, she finds a photo that has a woman who looks exactly like her and her boyfriend is beside the woman.
Going to the past year, 17-year-old Chen Yun-Ru meets her school friends Li Zi-Wei and Mo Jun-Jie. Back to the present, Huang Yu-Xuan is disappointed to find out that the man in the photo is not her boyfriend.
In 1998, Chen Yun-Ru is unconscious in the hospital after a stranger's attack. Meanwhile, in the present, Huang Yu-Xuan falls asleep listening to an old tape and wakes up, becoming Chen Yun-Ru.
Huang Yu-Xuan finds herself back in 2019, and although she goes to a mental hospital, the doctor does not believe her. Meanwhile, she receives Chen Yun-Ru's diary from the 32 Cafe's owner.
Huang Yu-Xuan prepares to go to Shanghai, but first she decides to go to the past once again; she finds out that Li Zi-Wei and Wang Quan-Sheng are different people, and she becomes confused that they look the same.
Mo Jun-Jie is accused of being the suspect in the attack of Chen Yun-Ru, but they go to the police to prove he is innocent; Chen Yun-Ru goes to her uncle to tell him she is Huang Yu-Xuan, but he does not believe her.
Li Zi-Wei encounters a lost girl, and he escorts her home safely; she tells him her name is Huang Yu-Xuan and to never forget her; Li Zi-Wei finds himself falling in love with Chen Yun-Ru.
Mo Jun-jie feels angry to hear Li Zi-Wei's affection toward Chen Yun-Ru, and that he will move to Canada after he graduates. Chen Yun-Ru tells her friends she is actually Huang Yu-Xuan from 2019, but nobody believes her.
A murder case arises at school, and Chen Yun-Ru instinctively feels relevant to the case. Meanwhile, Li Zi-Wei wakes up as Wang Quan-Sheng of 2010 after a car accident in 2003.
Li Zi-Wei wakes up in Wang Quan-Sheng's body in the future. Wang Quan-Sheng studies hard to go to the same university as Huang Yu-Xuan, but soon he is disappointed to find her with another man.
