Someday or One Day

Huang Yu-Xian 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.

Chen Yun-Ru thinks her being Huang Yu-Xuan was all a dream. Meanwhile, Chen Yun-Ru, Li Zi-Wei and Mo Jun-Jie try to find the attacker.

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.