Hotaru Kusakari is a pharmacist who usually works at just an ordinary pharmacy. However contrary to her everyday appearance, she’s a descendant of the Koga Ninja clan, taking on the long tradition that has continued since the ancient times. She acts in a calm and reserved manner, but this is only her outward mannerisms of meekness and stealth to prevent her identity from being discovered. In fact, she is feistier than others, a perfectionist who hates failure and defeat, and sometimes her real intentions burst out in ways of a sharp tongue. She also trains her physical prowess through stoic jogging sessions and training every morning and spends her days behaving secretly in a ninja-like manner. At the age of 28, she married Goro Kusakari an ordinary guy (or so she thinks). She is proud to be a member of the ‘Koga clan’ but after she met him, her longing for a normal household begins to come out…