Yuan Xin made a "ten-year agreement" with him. But when he appeared next to Yuan Xin, Yuan Xin didn't know that the person in front of her who liked to bicker with her was her "rival" when she was a child. Same grades, admitted to the same high school, and entered the same class! Yuan Xin, who loves to tease people, competes with him. The sweet night in the lost forest, the first kiss under that trap! Maybe there is an arrangement somewhere! When they had a heart-to-heart relationship, they realized what a farce it was! They could be brother and sister! But what exactly is the ending? A huge conspiracy is quietly revealed...