Fujiko goads Lupin into stealing a large shipment of diamonds. Lupin takes the task despite Jigen protests that Fujiko is playing them for fools. Of course, Jigen is right. Just who will end up with the diamonds?
Someone is committing thefts under Lupin's name. Lupin follows the impostors back to their island hideout. He has apparently stumbled into a whole island of thieves. Can Lupin learn their secrets and escape with his life?