In this animated sequel to Atlantis: The Lost Empire, the discoverer of the submerged continent, Milo (James Arnold Taylor), and his new wife, Queen Kida (Cree Summer), are startled when friends led by explorer Preston (John Mahoney) tell them that the monsters meant to protect their land are causing destruction on the surface. Milo travels with Preston and his crew to Iceland, Arizona and Norway to stop the havoc, while Kida considers having Atlantis make contact with the outside world.