While in the middle of a battle against sea monsters who are attacking KatCo oil tankers, the Swat Kats become caught in of the Pastmaster's time portals, which appears out of nowhere and pulls them back into medieval times. There they find the evil wizard in the midst of laying siege to Megalith City, Megakat City's Dark Ages counterpart, with an army of mythological monsters (dragons, cyclopes, etc.) in an effort to force its ruler, Queen Callista, Callie Briggs' lookalike ancestor, to marry him. And that's not the only romantic complication! When Callista sees Razor pull a certain sword from a certain stone, she falls in love with him, causing T-Bone to become jealous.