In an imaginary dynasty, Yinyin, the number one killer of the Black Feather Organization, has a naive mind and a kind nature. Due to the "disbandment" of the organization, he accidentally met the third prince Junlin who cared about the common people, and was hired as a personal bodyguard. The two gradually fell in love while pacifying mountain bandits, punishing bullies, fighting against the Ninth Prince Junhe's frame-up, and tracking down poisoning and assassination plots. In the end, Yinyin discovered that Black Feather was still around and was suspected of participating in the assassination against Junlin, and they faced the crisis together with Junlin.
