The film follows Milo Thatch, a grandson of the great Thaddeus Thatch who believes that Atlantis is real and he can get there with the guidances of the mysterious Shephards journal. Milo meets a woman when he returns home who takes him to Preston B. Whitmore, an old friend of his grandfather to get the Shephards journal, a submarine and a 5-star crew, and they start their adventure to Atlantis.