The female lead, Yin Xi, is from the Tang dynasty. After eating a fruit that grants eternal life, she has lived for 1,450 years, from ancient times to the present day.
The male lead, Li Shimin, is an emperor of the Tang dynasty. He is assassinated while hunting and accidentally falls into a time rift, transmigrating to the modern day.
In the Tang dynasty, Yin Xi is the younger sister of a general. After her brother is framed, the emperor orders the extermination of his entire clan. With help from her family, Yin Xi escapes this fate and accidentally eats the fruit that grants eternal life.
As a result, she lives on into the 21st century, all the way to 2024.
But one day, to Yin Xi's utter surprise, Li Shimin transmigrates to the modern day and encounters her, still immortal. She recognizes him at once, but Li Shimin doesn't recognize her.
As Yin Xi searches for a way to transmigrate back to the Tang dynasty, she takes revenge on Li Shimin in the modern world, making his life even more difficult. Only then does he remember Yin Xi. He has met her before, but never imagined that she was still alive, let alone that she had lived for over a thousand years.
At first, Li Shimin thinks Yin Xi has simply transmigrated to the modern day too.
The two begin tormenting each other.
Later in the story, Li Shimin finally finds the time rift and takes Yin Xi back to the Tang dynasty with him. They reopen the investigation into the general's wrongful framing and clear his name.
While investigating in the Tang dynasty, they discover that they had already admired each other back in the modern world.
After everything is resolved, Li Shimin brings Yin Xi into his harem and makes her a Talented Lady.
In the Tang dynasty, Yin Xi changes her name to Wu Meiniang.
