According to mystery novels written by mochizuki mai, there exists an antique store in kyoto's teramachi sanjo shopping district. in this shop, a high school student named mashiro aoi stumbles upon yagashira kiyotaka, the son of the shop owner, and begins working part-time at the store. kiyotaka is often referred to as "holmes at teramachi sanjou," and he and aoi collaborate on solving peculiar cases that are brought to them by customers.