Arcane is possessed by evil spirits when he tries to practice voodoo.

The Swamp Thing is struggling to remain hopeful that he will be human again. Someone from the past comes to visit him, using Will to guide her to him. Only Will does not believe that she is who she says she is, and he is about to learn who he can and cannot trust.

When a killer mist emerges from the swamp and invades Houma, the Swamp Thing and Arcane must team up to try to stop it before it decimates the whole town. Meanwhile, Will and Abigail race to warn the town.

Will has a secret from his past that comes back to haunt him. The swamp forces Will to face his inner demons, as well as the visitors that he does not know are waiting for him at the house.

Ann Fisk, a scientist and former student of Alec Holland, is in town. Ann's mentor, Carter LaRoche, has designs to build a recycling factory under Arcane's financing in the swamp. Ann must trust a strange voice in the swamp to expose an evil that she is not aware of.

Will falls in love with a lovely carnival worker named Amanda. Yet, Will becomes aware that Amanda is being held against her will by the shady carnie owner, Hurley, who has a dark agenda for Will.

Arcane is judged by the victims of his evil when he is killed by a laboratory accident. In this mock trial, he finds out who hates him and why, while he unsuccessfully tries to defend himself.

Ian James, an unscrupulous anthropologist, has come to the swamp to create a reputation for himself and the swamp suffers for it. Tressa is quite taken with him and in the process, the Swamp Thing is caught on film.

Nathan Stone is a heavy metal musician staying alone in the Kipp boarding house where the Swamp Thing terrorizes him with a series of mind games as he seeks to teach the shallow and egotistical rock star to take responsibility for his wicked lyrics that have led to the suicide of two teenage fans.

Will is taken hostage by two greedy explorers who force him to help them find the location of a mystic Mayan temple in the swamp, housing buried treasure and ghosts.