This is a story about oneself falling in love with another self in the body, and then the self in the body finds that the other self in reality falls in love with the original self in the body, and he becomes his love rival.
If you are confused, let me give you a normal explanation: a heroine who is horrified to discover that she has a "dual personality" gradually falls in love with her second personality. As the male protagonist's second personality, he discovered that there was another version of himself from five years ago in reality, and that person from five years ago slowly fell in love with the female protagonist, so he himself became his love rival again.
Still can't understand? ... Forget it, let's read the article.
Concept: Men and women always have very different views on the same thing, but if a man and a woman live in the same body, how will they deal with it? If the two people had the same perspective and situation, would there be different results?