Inspector Zenigata has been shot by a Walther P38! The prime suspect? Lupin the Third.

Lupin is framed for the murder of Inspector Zenigata by a mysterious assailant holding a silver-coloured Walther P38 pistol Lupin himself once owned. Tracking the true killer leads Lupin to the island of the bloodthirsty Tarantula assassins inside the Devil’s Triangle. After joining the spider-tattooed army against their will, Lupin and his gang make both new friends and enemies as they not only plan to take home the Tarantulas’ massive gold repository for themselves, but hunt down the shooter from Lupin’s past. Can Lupin put to rest this demon who haunts his memories with the Walther P38?