Lupin and his gang were pursuing Flight 107, when Soviet Union planes suddenly shoot it down for wandering into its territory inadvertently. To Lupin’s despair, the now sunken Flight 107 was carrying a ring called the Star of Alaska, or in Lupin’s mind, his engagement ring to Fujiko. Fujiko had told Lupin that she’d marry him if he gets the Star of Alaska for her, but Lupin soon finds out the CIA and KGB are also after the Star of Alaska. What secret does the Star of Alaska hold and is it truly at the bottom of the ocean?