Deep in the swamp, a mutated fly lurks.
Swamp Thing takes Jim through the swamp, explaining that much of it is untouched the way nature meant it to be. He shows the boy flowers and how many of them are almost extinct because of people. They come to a fog-covered grove of mutant plants, and Swamp Thing tells Jim not to enter because it's dangerous. He refuses to tell Jim why it's dangerous, and tells him to stay away.
Later back at home, Jim wonders what Swamp Thing didn't want him to see. He goes back on his own but hesitates to enter the grove. When Jim starts to go back, the fly bites him on the neck.
That night, the EMTs arrive at the Kipp house when Jim collapses. They take him to the hospital and Tressa paces nervously outside her son's room. Dr. Cass Muir comes in and explains that he's an infectious disease specialist called in on Jim's case. He explains that there's a venom in Jim's system, and Tressa says that her son was in the swamp just before he got ill. Muir goes in with Tressa to examine Jim, unaware that the fly is still there. The doctor finds a bite on Jim's neck and two spots of blood on the pillow, and he warns that they can't analyze the venom without a sample.
Arcane arrives and Tressa explains about the poisonous bite. Muir says that there's more than one venom in the mix, and what bit Jim was a hybrid. Arcane argues with Muir, and Tressa tells Arcane that she'll call if she needs anything. Outside, Arcane steals a lab coat and tells the nurse at the desk that Tressa asked him to look in on Jim. He goes in and examines the bite. When the nurse comes in to get his name, Arcane quickly leaves.
In the swamp, Swamp Thing remembers what Jim said about wandering around and realizes that it's his fault that Jim was bitten. He sneaks into the hospital and senses the fly nearby. Swamp Thing ducks through a door as two nurses go by, and then realizes that it's an emergency exit that doesn't open from his side.
Muir finds Tressa at Jim's side and says that they have a bed for her. She reluctantly goes to the adjoining room and washes up, and the fly enters the room. It bites her on the arm and she calls to Muir, and slams the door shut to try and trap it so that they can get a specimen. Tressa finally manages to trap it with a bowl against the wall, and tries to reach the bell without releasing it. When she can't reach it, Tressa yells for help.
The next day after they find Tressa, Muir examines the fly and tells Tressa that she did good. Meanwhile, Swamp Thing crawls into the ceiling and gets to Jim's room. He climbs down and tells the unconscious Jim that it will be all right. Swamp Thing transfuses some of his fluids into Jim's body.
Tressa starts to collapse, and Muir says that she needs some rest and he'll tell her if there's any change. Muir's associate, Bloom, says that he's identified the venom's chemical properties and can make the antidote. Tressa goes to Jim's room. Swamp Thing finishes and gets out just in time. She's surprised to discover that Jim is awake and well. The bite marks are gone, and Jim sees the green liquid in the transfusion tube and realizes what happened. Tressa is too relieved that her son is all right to ask any questions.
Later at the grove, Swamp Thing realizes that Arcane created the fly. He vows that he will always stop Arcane.
Written by Gadfly on Jun 13, 2017