In their memories, there is a period of youth, where they have lost their purity.
Everyone has his own world, and in that world, you are the king. Wang Kexin is obsessed with his own world. He is aloof and cannot see the pain of others.
Zhan Xiaoyu also has a world of her own. In her world, she is obsessed with her own direction. As for those who are not in that direction but love her deeply, Zhan Xiaoyu cannot see them all.
Our hearts are a mystery, and so is our world.