The film begins with a large tidal wave, triggered by a distant explosion, which threatens to drown the island of Atlantis. In the midst of an evacuation from the capital city, the Queen of Atlantis is caught by a strange, hypnotic blue light and lifted up into the "Heart of Atlantis", a powerful crystal protecting the city. The crystal consumes her and creates a dome barrier that protects the city's innermost district. She leaves behind a young daughter, Princess Kida, as the island sinks beneath the ocean. Several thousand years later, in 1914, Milo Thatch—a cartographer and linguist at the Smithsonian Institution who is marginalized for his research on Atlantis—believes that he has found The Shepherd's Journal, an ancient manuscript allegedly containing directions to the lost island. After his proposal to search for the Journal is rejected by the museum board, a mysterious woman, Helga Sinclair, introduces Milo to Preston B. Whitmore, an eccentric millionaire. Whitmore has already funded a successful effort to retrieve the Journal as repayment of a debt to Milo's grandfather, and recruits Milo to lead an expedition to Atlantis as soon as he deciphers it.