No one understands the bitterness in the sentence "Looking up is more painful than secret love" than Liu Sidong. Her love has a long way to go, as if hanging for nine days. Falling in love with an idol will result in nine out of ten injuries, but she is so obsessed with love that she takes pleasure in suffering. However, the Black Knight accidentally bumped into her world, and the peaceful life that had been silent for nearly thirty years suddenly became turbulent. What is even more unexpected is that the entanglement between the three people is far from simple love.