Yotaro Hanafusa comes from a lineage known as the “Knights of the World” who instilled the Knight’s Code of Chivalry in him from a young age. Driven by this, Yotaro has a habit of rescuing women in need and he goes incognito with a mask as “Knight Lancer” when he wanders around town. However, he always remains anonymous. During a leisurely outing, Yotaro saves a six-year-old girl named Makio Kidoin, the only offspring of a prominent business magnate. After discovering Makio’s solitary lifestyle in a sprawling estate, Yotaro makes up his mind to keep her safe. To accomplish this, he and his pals pose as tenants and relocate to her residence.