The story follows a high school girl named Aoi, who has just moved to Kyoto from her home up in Tokyo after the ending of a rocky relationship. Upon wandering the covered arcade street Teramachi, she finds a little antique shop, in which a university student, Kiyotaka, works. Kiyotaka is an enigmatic young man who people often come to in order to solve little mysteries about their antiques, and for that–as well as other reasons explored in the book–he is granted the nickname "Holmes". As such, Aoi slowly but surely becomes the "Watson" in the tale as she starts a part-time job at the antique shop and learns more about his family and Kyoto as a whole.