Inspector Karikiri and Takeo's father, Shoichiro, were childhood friends. The two meet again for the first time in a long time, hit it off, and have a drink at Shoichiro's house. Shoichiro had just discovered some earthenware in Shinshu and brought it back with him, so he earnestly asked the Metropolitan Police Department to have it examined in detail. As a result of the appraisal, it was determined that the pottery that Shoichiro discovered was a national treasure.