Three game designers arrive at Kogoro's agency to ask for his assistance to look for their game programmer Subaru Itakara. He was last heard in a video mail which shows him in a hotel with an igo, shogi, and chess set. One of the game producers believe that a mysterious man may be the cause of Itakara's disappearance; Conan realizes from his description the man is Tequila from the Black Organization. Kogoro decides to call hotels and ask them if anyone rented a shogi, chess, and igo set at once. After learning of Itakara's hotel and room number, they enter the apartment only to find out Itakara had died of a stroke. The police's investigation reveals that Itagara's body was tied up before his death; This means someone tied him up to prevent him from being able to take his medicine which would have prevented the stroke. Further investigation reveals that someone other than Kogoro also phoned the hotel asking for a person with a shogi, chess, and igo set; Since the three producers are the only ones who knew Itakara had those three sets and was staying in a hotel, this makes them the prime suspects for murder.