Kyoto Teramachi Sanjou no Holmes

Half a year after moving to Kyoto, high school girl Aoi Mashiro brings her late grandfather's old scrolls to Kura, an antique store nestled in Kyoto's Teramachi-Sanjo shopping arcade, for an appraisal. One thing leads to another, and she winds up working there part-time. The manager's son, Kiyotaka Yagashira—nicknamed the "Holmes of Kyoto"—is uncannily perceptive, and together, they solve strange cases relating to the antiques brought to them by clients. (Source: J-Novel Club)