Professor Hackle intends to reprogram the Metallikats to be good, but Mac and Molly escape from his lab before he can. In search of their armored hovercraft, the Metallikat Express, they wind up in the salvage yard near Jake 'n' Chance's Garage. There, they inadvertently discover the hidden Swat Kats hangar and thus uncover the secret identities of the vigilantes themselves! Chance and Jake, in their civvies, must defend their own base from the murderous, mechanical gangsters. Although their bodies are destroyed, the Metallikats survive as disembodied heads crawling around on spiderlike legs, and eventually take control of two Puma-Dyne Macrobots, giant and powerful space exploration robots, and begin to trash the city. Now, the Swat Kats must stop the Metallikats from revealing their secret and save the city!