As the editor-in-chief of the underworld, Bai Wuchang, Xie Bi'an was sent to the human world to be a nanny due to a work mistake, protecting a three-year-old cub with a very lucky fate. In order to complete the task, he had to find a yang-yang "hard-failed" person to agree to marry. So, he handed the contract to Su Xiao, a girl with a bad luck and a "crow's mouth" who always speaks the opposite. From then on, Leng Mian Yin Cha was forced to learn how to make milk powder, change diapers, and always have to deal with all kinds of outrageous situations caused by his "wife" casually saying "unlucky". It wasn't until the evil cultivators and evil spirits came upon the news that Xie Bi'an discovered that Su Xiao's "crow's mouth" that deceived the whole family had become the ultimate weapon to follow the rules when protecting his family.
