Koiko, known as the princess of love, possessed the ability to make people admire her at will. However, this power was to fade away once she attained maturity and got married. Amongst those she had never used this power on was Shirou, a boy who she had trusted. However, when he didn't keep his promise of showing up, Koiko discovered that he was actually a famed shadow ninja. The revelation left her heartbroken, and she set out to find him, only to learn things about him that were previously unknown to her.