The year is 2019. A 27-year-old woman named Huang Yu Xuan (Alice Ke) pines for the love of her life, her long-time boyfriend Wang Quan Sheng (Greg Han), constantly checking his social media pages and desperately hoping he will call her, asking to get back together. But one fateful night, Huang Yu Xuan is hit by a car. She regains consciousness and sees a man she believes to be Wang Quan Sheng sitting by her hospital bedside. She believes she has finally been reunited with her beloved Wang Quan Sheng! But there's a very big twist. She learns that she is no longer a 27-year-old woman, but is now a high school student named Chen Yan Ru. The year is now 1998. And the man by her bedside is not her boyfriend after all, but a schoolmate named Li Zi Wei. Trapped in what appears to be the past, living another person's life, she eventually comes to realize that the traffic "accident" that landed Huang Yu Xuan in hospital may not have been an accident after all. And Chen Yan Ru's own reasons for being hospitalized are also shrouded in mystery. All the while, Li Zi Wei finds himself strangely drawn to the woman who used to be Chen Yan Ru, despite the fact that he knows his closest friend Mo Jun Jie (Patrick Shih) has had a crush on Chen Yan Ru for years... Can true love find a way to bridge a seemingly insurmountable time gap? And what really happened on the fateful night when Huang Yu Xuan was hit by the car? "Some Day or One Day" is a 2019 Taiwanese drama series directed by Huang Tian Ren.