When a team of scientist led by Dr. Irwin Burns (Joseph Ruskin), tests an experimental drug that increases aggression in animals and humans, their biochemical lab explodes and a mutated nightmare escapes. Half African King Cobra and half Eastern Diamondback Rattlesnake, Seth is pure evil. He's 30 feet long with a giant appetite for terror! As the nearby town of Fillmore prepares for its annual lager beer festival, Seth moves in for the kill, turning celebration into fear and panic. With hundreds of innocent lives in danger and time running out, Dr. Brad Kagen (Scott Brandon) and his girlfriend, Deputy Sheriff Jo Biddle (Kasey Fallo) hire a renowned snake expert Nick Hasimoto (Pat Morita) to lure Seth into a deadly trap. But this is one intelligent predator and the battle between man and reptile soon escalates into an all-out war for survival.