In the Mediterranean Sea, there's Colcaca Island, where a war is in progress between 2 sides, One lead by Carlos, and the other lead by Consano. These 2 leaders were once partners in a treasure hunting business, but they went their separate ways in finding Hemingway's treasure. When Lupin heard about this he heads over to Colcaca to check this whole conflict out. Only to discover that Jigen and Goemon are on opposites of the war with their own reason. Fujiko becomes a secretary of Mr. Marcess, a wealthy arms merchant who owns the key to revealing Hemingway's Documents that tell where Hemingway's treasure is on Colcaca island. So Lupin decides to help Jigen and Goemon's problems, and get to the treasure before any of the armies do.