When Doraemon and his pals create a time portal, they find themselves in the Country of Mayana, a hidden Mayan realm deep in the jungle. In this mysterious land, Nobita encounters his doppelganger, Prince Thio, next in line for the throne. To rescue Mayana from the clutches of the wicked witch Ledina and her dark minions, Nobita and Thio swap identities in a daring attempt to protect the ancient civilization.