Shortly after receiving an anonymous check for $5 million, H.E.A.T. are called toIllinois, where a gigantic mutated chilopod, Megapede, is devouring thousands of dollars worth of crops. The team are unable to stop the creature when they first encounter it, and upon finding it again, they discover it has metamorphosed into a gigantic cicada. The insect's mating call is disrupting all radar in Chicago, and now H.E.A.T must find a way to silence the creature long enough to launch a counterattack.

Just as H.E.A.T has had it with Randy, Elsie convinces the rest of the team to investigate a possible mutation sighting at Area 51, where they discover the real secret of Area 51 is not aliens, but mutations, created by underground nuclear testing. When one of the captive mutations - a mutant thorny devil lizard - breaks out of its cage, the team and Godzilla must stop the creature from escaping the base and destroying nearby Las Vegas.

During a nice relaxing day at the beach, the team is caught off-guard by a twister. They trace its origins to an experimental energy experiment at a local power plant, as well as discovering strange tracks near the plant. When the twister strikes again, H.E.A.T. discover that a giant mutant shrew has been bonded to the twister, creating a 'Shrewster', and now the race is on to defeat it before its ravenous metabolism drives it to eat all of New York.