Episode 1

Hotaru Kusakari, a pharmacist at an ordinary pharmacy, and Goro, a clerk at the Setagaya Central Post Office, have been married for two and a half years. However, they were only in love at the beginning of their marriage, and due to differences in lifestyles and values, they started arguing over trifles every day, and they were already facing a divorce crisis. In fact, Hotaru and Goro have a "backside" that they can never tell anyone about. Hotaru is a Koga ninja, and Goro is an Iga ninja, descendants of rival ninjas who are said to have continued their rivalry behind the scenes of Japanese history. However, both of them are living a married life without realizing each other's true identities. At that time, Hotaru receives an order to grasp the scandal of Shosuke Akamaki, a Diet member of the ruling Minjito. On the other hand, the Akamaki side, who sensed suspicious movements in the surrounding area, secretly asked the Iga clan to protect them.