Su Qingtang, the daughter of a reclusive medical sage, was forced by the Righteous Dao to marry Xiao Wang, the yandere demon king who was bloodbathed in the three realms because of her teacher's annihilation. I thought it was a sheep falling into a tiger's mouth, but after getting along with Xiao Wan day and night, I discovered the truth that there was an ancient evil spirit sealed in his body, and he looked cruel but was actually lonely. The two went from testing each other to joining forces to break the situation. Qingtang used poison to resolve the backlash of the evil spirit in the demon king's body. Xiao Wang faced the righteous encirclement and suppression to protect her. In the conspiracy and affection, they staged a sweet and sad drama of marriage first and love later, and two-way redemption. The highlights focus on Qingtangzhi breaking the drug bureau, Xiao Wang protecting his wife and getting slapped in the face, and the two teaming up to overturn the hypocritical mask of justice and other high-profile scenes.