The team is split up due to a lawsuit by the state of Miami (over damages caused by a giant vampire bat). While Nick, Monique, and Elsie deal with the lawsuit, Randy and Mendel decide to deal with a mutant (without Nick's permission) in Michigan. The mutant in question is Armillaria, a giant fungus with the ability to suck the amino acids out of any living thing. It swiftly proves too much for the duo, who end up trapped in the wilderness with nothing but their wits and the clothes on their backs. Once the others hear of their antics, the race is on to rescue the duo and defeat Armillaria before it sucks Godzilla dry.

While in New Orleans covering Mardi Gras, Audrey hears rumours of a strange 'Swamp Beast' and decides to call in H.E.A.T.. The creature swiftly proves itself a match for Godzilla, and the team begin to suspect something is afoot when the locals claim the beast is the swamp's revenge against corrupt local politician, Paul Dimanche, who wants to mine oil in the bayou. But can they prove it before the Swamp Beast destroys New Orleans?