While on leave from the Navy in Shanghai, Donald Duck agrees to meet Scrooge and his nephews. The Navy is near Shanghai, testing out McDuck Enterprises’ new submarine. However, a deadly agent uses the charms of a young woman named Cinnamon Ti, to hypnotize Donald and bring him the control panel to the sub. Now it is up to Scrooge and the boys to clear Donald’s name and stop the spies from using the sub for their own evil purposes.