In 1914, the young scientist Milo Thatch firmly believes that the legend of the sunken city of Atlantis is true. Mr. Whitmore, a billionaire entrepreneur and old friend of his late grandfather, offers Milo to fund his expedition to Atlantis because he wants proof of the Atlantis theory. For the expedition to Atlantis, Mr. Whitmore has already assembled a team of experts, which Milo will complete as a cartographer and linguist.