In order to save his childhood sweetheart, high school sophomore Shang Yayue signed a contract with the nine-tailed fox prince Si Yan and became his bride-to-be. She also took on the important task of breaking the seven seals and maintaining the balance between the human world and the demon world. When a confused and lovely human girl meets a fox demon boy who is sometimes gentle and sometimes cold, when a pure heart encounters all kinds of worldly temptations, when dishonest words encounter fatal misunderstandings, when a slowly deepening love encounters feelings that have been buried for many years... When everything blooms like fireworks and then quickly dissipates, the last thing left is - she and he like each other, this iron-clad fact.