Milo Thatch, a young linguist, embarks on an expedition with a group of explorers to find the lost continent of Atlantis. Along the way, they encounter danger, strange creatures, and the Atlantean civilization. As they delve deeper into the mysteries of Atlantis, they discover the truth behind the crystal that connects the Atlanteans and the treacherous plans of some expedition members.
Milo, Kida, and their friends return to Atlantis to stop a dangerous villain from using an ancient artifact for evil, encountering sea battles, mind control, and mythical creatures along the way.