Ep. 3: Dubious Move episode details the mystery of Kinzo's disappearance and the locked room murders.

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While attempting to figure out what happened, the remaining guests discover that their radio is not working, leaving them stranded on the island with the culprit until the typhoon passes. They quickly discover that Kinzo has gone missing as well. Battler and the rest of the family theorize that one of the eighteen people on the island is posing as Beatrice in an attempt to claim Kinzo's inheritance. The primary suspects are the servants, who have access to the entire mansion; Natsuhi, the last person seen with Kinzo; and Eva, who has the most to gain from the murders. After a heated argument between Natsuhi and Eva, they are unable to come to a definitive answer and return to their rooms. Later, Eva and Hideyoshi are found dead with stakes embedded in their foreheads in their locked room. (Source: Wikipedia)