Because of love, a boy is willing to pretend to be a 17-year-old girl for another boy. Just when their love is in full swing, Xichen knows the secret of 17 that was buried by his mother, so he can only break up with Chenxi. But a week later, two new students are transferred to Chenxi's class, a pair of brothers and sisters. What is even more surprising is that the brother looks like Chenxi, but the sister looks like the original Chenyi. How will the story develop?