Set in 1914, young linguist orphan named Milo Thatch buries himself in books trying to unlock the secret to the destruction of Atlantis. Althouth his theories are ridiculed by his colleagues he is persistent in his dreams of one day discovering the lost isle. His dreams are realized when he is given a spot in an expedition, financed by a friend of his grandfather, to go in search of Atlantis following Milo's guide: The Shepard's Journal. But the Guardians of Atlantis await the explorers putting them in danger at every turn. And the deadly truth about Atlantis's demise puts Milo, the royal family, and all of Atlantis in mortal jeopardy.

Jim Varney (Cookie) died just before finishing the film. The "I ain't so good at speechifying" line near the end is the only line not spoken by Varney. 'Steven Barr (I)' did the voice for that scene.

Princess Kida:
You do swim, do you not?


Milo:
Oh, I swim pretty girl... Pr-Pretty *good*, pretty good. Sw... Good. Swim good. Pretty good. I swim pretty good.

Factual errors: When Milo is rehearsing his proposal in the museum basement, he rubs against the chalkboard and wipes the map he drew onto his clothes. He then stands in front of the chalkboard and the chalk map on his clothes matches the missing part of the map, when in fact it should be a mirror image.

Lyrics by Diane Warren
Music by Diane Warren and James Newton Howard
Performed by Mya
Mya appears courtesy of A&M Records