In an old graveyard outside Megakat City, grave robbers are digging around for valuable artifacts when they find a large chest. Inside they find the Pastmaster, an ancient evil wizard who was imprisoned within the chest 800 years ago. The Pastmaster heads to the Megakat City Museum of History to search for his spell book, the Tome of Time. Callie Briggs is at the museum preparing for the opening and summons the SWAT Kats to help defeat the Pastmaster. After locating his spell book, the Pastmaster wants to bring back the Dark Ages and opens a time vortex that brings a “Megasaurus Rex” to the present time. The SWAT Kats are sucked into the portal and are sent back to the time of the dinosaurs. As the Pastmaster ravages Megakat City with the Megasaurus Rex, the SWAT Kats try to get back to the present and prevent the Pastmaster from casting a spell to bring the Dark Ages to the present.