- "The wrath...of nature...is not wrong...Nor is it unjust...that man...should bear its brunt."
— The Swamp Thing
The title character, in search of Abby, speeds toward Gotham City through the Green, leaving a trail of fresh vegetation in his wake. Meanwhile, Dwight Wicker, head of the DDI—the covert quasi-governmental organization that captured the Swamp Thing for General Sunderland—meets with Police Commissioner James Gordon and Detective Harvey Bullock, requesting access to Abby. He explains that the Swamp Thing is wanted for the murder of Sunderland, and Abby's arrest for cohabitation with him is the first lead Wicker's had in the two years since. Gordon, already wary of Wicker's intentions, refuses to cooperate after Bullock informs him about the psychological damage the DDI did to Abby's husband Matt, and about rumours of DDI involvement in the West Virginia operation that destroyed the Cables' home. The Commissioner tells Wicker Gotham has its own resources for dealing with monsters.
As the Swamp Thing nears Arkham Asylum, he notices the Floronic Man's disturbed aura and materializes in his cell just to check on him. Woodrue is terrified, thinking the "swamp god" has come to punish him for his manipulation of the Green against humanity. The Swamp Thing, however, forgives Woodrue, assuring him he wasn't wrong to be angry, at least, with humankind, and that he's there to bring judgement not on him but on Gotham.
A mob crowds Abby as the police bring her to the courthouse for her extradition hearing, and a women's group hands her a rose in support. Psychically hearing her lover contact her from the Green, she tunes out of her surroundings and focuses only on him, even once she's inside and the hearing begins. Ignoring the judge, she assures "Alec" out loud that she's unharmed, and he tells her to let go of the rose. As the judge is on the verge of charging her with contempt of court, the Swamp Thing bursts up through the floor amid a garland of roses.
Disarming a police officer who draws a gun on him, and hemming in several people with trees and vines, the Swamp Thing announces he's there to rescue Abby. Undaunted, Bullock says Abby must stand trial in Louisiana, and threatens, along with other cops, to open fire on him. Concerned that someone will get hurt as a result, Abby begs her lover to stand down for the moment. The Swamp Thing agrees, but warns the authorities that he's put up with humans damaging the environment long enough, and that if "nature were to shrug," they'd be gone. He tells them they have an hour to give him back his wife, and departs, leaving a trail of flowers and tomatoes.
DDI higher-ups watch footage of the incident and wonder how, or even whether, the Swamp Thing can be killed now he's grown so powerful. Wicker, intent on eliminating the creature as a witness to the agency's crimes, introduces an expert who's charging them a million dollars for a ten-minute consultation on how to do so: Lex Luthor.
Once an hour has passed without them returning Abby to him, the Swamp Thing decides to show the city authorities he means business. He overruns all of Gotham with vegetation of all kinds, turning it into a jungle. Some residents find this enchanting and strip naked to frolic among the newly-grown trees and bushes. Watching from a distance, the Swamp Thing wonders why he didn't do something like this sooner, but also reminds himself there's someone else watching over Gotham. The issue ends with a full-page shot of an angry Batman.
- Arc Words: "One thing leads to another," in line with the issue title.
- Beware the Nice Ones: The Swamp Thing normally avoids violence and gratuitous gestures of power, but lay a finger on Abby...
- Call-Back: To The Anatomy Lesson, in which a temporarily deranged Swamp Thing smothers Sunderland to death.
- Children Are Innocent: The first people to embrace Gotham's newly-green state are young children.
- Cut Lex Luthor a Check: This and the following issue are the Trope Codifier. At this early point in Post-Crisis continuity Luthor, as far as the general public knows, is a reputable businessman, but Wicker presumably knows of his ongoing battle with Superman, and thus that he's an expert on dealing with nigh-invulnerable beings. As such, Luthor is willing to capitalize on this expertise, in a technically legal way.
- Gaia's Vengeance: Before reverting Gotham to a jungle, the Swamp Thing, like Woodrue before him, lambastes the human race for its destruction of the environment. Indeed, he speaks as though he were nature itself:You...are warning...me...? Do...you warn...the hurricane? Do you warn...the earthquake? [...] [Y]ou cannot...shoot the forest. [...] Fools, if nature were to shrug...or raise an eyebrow...then you should all be gone...
- Green Thumb: Again like Woodrue before him, the Swamp Thing uses this power as a weapon against an entire city. Unlike Woodrue, however, he does so in a way that's non-lethal, albeit destructive to property.
- Hearing Voices: As the Swamp Thing leaves his cell, Woodrue begs him not to leave him alone with "the voices."
- Iris Out: This appears in the sequence of panels where Abby notices Alec contacting her from the Green, and she blocks out awareness of anything else.
- Love Is in the Air: When the Swamp Thing turns Gotham into wilderness, particularly susceptible people—"the derelicts, the criminals, the lovers"—shed their clothing and have a love-in.
- Mistaken For Crazy: When Abby tunes out of her surroundings in court and then talks out loud with her lover (whom the others can't hear), her public defender makes the circling-finger-beside-the-head "crazy" gesture to himself, and the judge asks the bailiff whether Abby's had the standard psychiatric exam.
- Nature Is Not Nice: The Swamp Thing, in his anger, says that humankind is only still around on nature's sufferance, but that could easily change.
- Psychic Link: By this point, Abby and the Swamp Thing have a functional two-way instance of this, enabling them to hold a conversation when physically separated.
- Reaction Shot: The panel in which Wicker announces that he's hired a consultant shows other DDI higher-ups gaping in shock. One of them lowers his shades; another lets his pipe fall from his mouth. In the next, extra-large panel, the reader sees why they're so taken aback: the consultant is Lex Luthor, sporting Evil Eyebrows and a Psychotic Smirk.
- Reasonable Authority Figure: Commissioner Gordon suspects that something's fishy about Wicker's request to see Abby; he tells Wicker that he doesn't see why a morals case requires federal government involvement. When Bullock confirms his suspicions by relating what he knows about the DDI's history with the Cables, Gordon confronts Wicker about his neglecting to tell him. Neither Wicker's invoking the phrase "national security" (as in Loose Ends), nor his claim that he only wants to "protect" Gotham, have any effect on Gordon, who simply tells Wicker that Gotham has its own means of protection.
- Unfazed Everyman: Harvey Bullock, apart from mild astonishment that a plant creature can talk, is unperturbed and certainly unintimidated at the sight of the angry Swamp Thing.The Swamp Thing: You can shoot...the animals...in the forest...But you cannot...shoot the forest.
Bullock: I think we can maybe chip the bark a little. —Men, if it moves, shoot it!
- When Trees Attack: In the courthouse, the Swamp Thing generates trees for this purpose.