Mr. Lupin has summoned all his companions to a secluded villa on an isolated island. It is the first reunion in five years. While everyone stays at the villa, Lupin is preparing a grand surprise; however, Fujiko, Goemon and Jigen notice his odd conduct. They also wonder who the iron‑masked man chained to a wall is, and why he has been restrained—answers they are about to discover in the dimly lit corridor where secrets linger and mysteries await tonight again.