Two days after his showdown with Godzilla, Kong and his burgeoning family set off on a Voyage across the Hollow Earth to discover all there is to see there. However, documentary filmmaker Carl Denham and his crew follow them, having been contracted by Monarch to do so. But, Kong soon meets the inhabitants of the Great Empire of Mu, who are being terrorized by the Serpent-Dragon Kaiju Manda. Kong soon steps up to protect them, teaming up with the Snapping Turtle Kaiju Gamera, guardian of Mu and friend to all children. Meanwhile, Kong also falls in love with the beautiful Ann Darrow, a member of Denham's crew.
