Manager Director Kodai Okuhira has everything: the looks, the smarts, the background, and a new, beautiful secretary, Yukino Miyachi... "Secretary", however, is not all that she is. She has appeared in his life on orders to kill him, as she is a highly skilled assassin! One day, as she is working on her mission to find out more about him, she ends up crossing paths with Kodai's naughty side and they end up spending the night together - without protection...! After that one night, it seems that Yukino's life completely changes! This is the story of a romance between a popular tactician and an inexperienced heroine with a double life! Will she be able to balance a life with her horn dog of a new husband as well as planning for his execution!?