The number one assassin of the Black Feather Organization, Yinyin, was extremely skilled in martial arts, but was forced to "lay off" because he spent all the organization's budget. In order to earn money to rebuild the organization, she accidentally became the personal secret guard of the tsundere third prince. The silly killer has a strange brain circuit, and all kinds of strange logic are confusing people. He is cute and serious at the same time. The arrogant prince was so angry at her various manipulations that his blood pressure soared, and he loved and hated her at the same time. At this point, the two people's funny daily life started as if they were happy enemies.
