11-year-old Jim Kipp and his mother, Tressa are spending some time at her mom's house in the swamps of Houma. Jim is introduced to the mysteries and the danger of the swamp while Tressa struggles to bond with Jim.
Dr. Arcane attempts once again to obtain the bio-restorative formula from the Swamp Thing. However, this time Arcane has a helper, and the Swamp Thing knows her as his late wife, Linda Holland.
Arcane has unleashed his latest mutant monster into the swamp to eat everything it sees and if this test trial works, then more will be released. To ensure that the Swamp Thing does not interfere, he takes a hostage and bargains for immunity.
Jim and Oboe sneak out on a midnight visit to the swamp to find the Swamp Maiden, who appears only once a year. Despite warnings from the Swamp Thing, they, along with a visitor from the newspaper, come to learn the meaning of "looks that kill".
Arcane's protégé, whom he refers to as the "Crown Prince", is experimenting with hatred pheromones and his latest batch, which supposedly failed, is dumped in the swamp. The Swamp Thing has to intervene when Tressa is exposed and is in danger of being murdered - by everyone.
The Swamp Thing is overcome by toxic waste and falls unconscious where he is found by two men and is sold to a carnival freak show run by a cruel man in league with Arcane. Jim stumbles upon the carnival and tries to help the Swamp Thing before it is too late.
Jim is feeling lonely and tries to make a new friend when he meets a mysterious young girl in town, named Lily, who invites herself into Jim and Tressa‘s home, and who carries a dark secret.
Jim and Tressa may have to leave the swamp after a lawyer delivers a notice of eviction in the form of a will from Tressa's late mother. They are unaware that the lawyer is in league with Dr. Arcane. Meanwhile, Tressa's mother's spirit guides her to the swamp where the real answers lie.
Arcane captures Jim and sells him into slavery after the boy is witness to the evil doctor's hideous transformations of men into monsters and the local sheriff is in on the plans. Jim's 17-year-old half-brother, Will, arrives to investigate Jim’s disappearance and teams up with the Swamp Thing to find him.
A runaway teenage synthetic human, named Abigail, escapes from Dr. Woodroe's lab when it explodes and is seen running through the streets by Will, who takes her in. Meanwhile, a baby is swept away by the waters of the swamp from the same explosion - and into the arms of the Swamp Thing.
Arcane plots and murders the local district attorney when he swears to bring Arcane down. A high profile murder tied to Arcane would be hard to hide, unless someone nobody would suspect commits the crime. Somebody like...the Swamp Thing.
Tressa and her friends are victims of another one of Arcane's experiments for General Sunderland. Tressa tries to save her friends when they suddenly disappear in the swamp right before her eyes.
Tressa accidentally uncovers a pair of robots casing the swamp and the Kipp residence in search of any evidence of Dr. Woodrue's experiments. Abigail is on the run and the Watchers must deal with the Swamp Thing to get to her.
Tempers flare when Will's estranged father shows up looking for a rare white orchid that Arcane has paid him to steal. Will's trust is broken, and so is the swamp's when he leads his father to it unwittingly. Meanwhile, Arcane tests his poisonous mutant garden on Abigail.
Arcane experiments on an innocent man by murdering him and trying to revive him with a serum, stolen from Alec Holland years ago. The man comes back to life again with severe side effects for anyone who touches him, even the Swamp Thing.
Romance and murder are in the air at the Arcane complex when he and his newest associate, Sienna, build a machine to make artificial earthquakes for General Sunderland. The two bicker and kiss back and forth as the earthquakes put Tressa and the Swamp Thing in serious danger.
An old adversary of Arcane is back in town and he has something Arcane wants. Tressa and Abigail are held hostage and the swamp takes a deadly blow as a result.
