Kyoto bustles with the arrival of the New Year and Aoi Mashiro continues to work at the antique store Kura in the Teramachi-Sanjo shopping district, alongside the owner's grandson, Kiyotaka Yagashira. On Valentine's Day, the two of them are invited to a storytelling session at the Yoshida-Sanso Inn, hosted by the popular mystery author Kurisu Aigasa. There they find out that someone tried to murder her three months ago, and her sister asks Kiyotaka to find the culprit.