Lupin and his gang were scoping out their next target, Macintosh Jewelry, the world’s most expensive jewelry store, when they end up inadvertently saving a young boy who was being kidnapped. Turns out, the boy is a genius and he possesses the data to a revolutionary invention that can turn seawater into fresh drinking water. In order to get his hands on the data, the owner of Macintosh Jewelry kidnaps Fujiko and demands the boy in exchange. Can Lupin protect the boy’s secret from Macintosh and who is the smartest of them all?