On the verge of a breakthrough in his quest to wipe out world hunger, botanist Alec Holland is placed under the protection of government agent Alice Cable. When paramilitary troops led by Anton Arcane try to steal the research, an accident turns Holland into the monstrous Swamp Thing.
After her mother's mysterious death, Abby Arcane travels to the Florida swamps to confront her stepfather, Dr. Anton Arcane. In an attempt to stave off aging, Dr. Arcane, assisted by Dr. Zurrell, combines genes from various swamp species, and tries to use his stepdaughter as a test subject—but she is rescued by the resurgent Swamp Thing.