He was the most difficult math problem in her youth, which she could not solve or forget.
She was the most unexpected sight for him on the podium, he couldn't avoid it or let go.
The five-year age difference and the identity of teacher and student lie between them like an unsolvable equation.
————————————————————————————
"Teacher Cheng, I like you."
"When you graduate, we will be together."
This is their agreement and her obsession.
But after the college entrance examination, she disappeared.
Four years later, she returned to her hometown, only to find that he had become a mathematics professor at her school.
"Lin Xiaoxia, you owe me an answer."
This time, he won't let go.
Concept: There is no right or wrong in love, but responsibility requires courage