Ichitarou is the heir to Nagasakiya, one of the largest commercial stores in Nihonbashi. He was born sickly and is unable to go outside as a result, but he is beloved by the spirits such as his friends, Sasuke and Jinkichi, who accompany and protect him. One night, Ichitarou sneaks out of his home and witnesses a murder, and thus begins his search for the culprit with the help of his spirit companions.