Somewhere in Florida, nuclear waste has leaked from an underground dump and caused mutant plants to grow. Desperate scientists have now asked you to enter the irradiated swamp and pick the plants so that they can experiment on them.
The plants in question are scattered throughout the horizontally scrolling swamp, which you traverse in an inflatable dingy. Energy-draining mutant animals attack throughout, causing you to call up a gun as your only means of defence.
Swamp Fever offers nothing special, but it's playable and entertaining enough for the money.