Since The New 52's launch, both Swamp Thing and Animal Man have been dealing with the same threat, known as The Rot. With the twelth issue of each series, the full crossover story Rotworld begins. Both #12 issues will be co-written by Scott Snyder and Jeff Lemire, and following that, both writer's books will diverge into their own point of view of the Rotworld story, with Rotworld: Kingdom of the Green and Rotworld: Kingdom of the Red story lines running in Swamp Thing and Animal Man. Additionally, Frankenstein, Agent of S.H.A.D.E., written by Matt Kindt, will feature a three part story arc titled Rotworld: Secrets of the Dead. When the story comes to an end, both Swamp Thing and Animal Man's plot lines will once again converge in two back to back issues.
Rotworld is first seen in an hallucination by Jacob Mullin, the Avatar of the Red during the late 19th century. He briefly glimpses the future (current-day in the DC Universe) of a destroyed city. Deceased and wasted away to bones and rags, various members of the Justice League (as well as Robin, Batwoman and Booster Gold) are seen staked up in the rubble and destruction. Mullin also meets in his vision the current-day Animal Man, Buddy Baker who tells him that the Rot will keep coming back until they win and how it has taken his family too. This immediately reminds Mullin of his own family and snaps out of the hallucination.
Having just beaten one of the Hunters Three who had possessed his old body Animal Man finally returns to his family after growing a new body thanks to The Red and the Parliament of Limbs. Not long after Buddy returns, his son, Cliff Baker who was abducted by the Hunters Three member, grows very sick. Having known that he would eventually need to find Alec Holland, the avatar of The Green in order to better fight The Rot, Buddy finds it imparitive that he needs to find Alec as soon as possible due to Cliff's illness, and leaves his son with his Grand Mother Mary Frazier, as he his wife Ellen Baker, daughter Maxine Baker and Parliament of Limbs member Socks set off to find Alec.
Socks helps lead Buddy to the middle of a nearby swamp where Buddy and his family find Alec, along with Abby Holland after the two had just sent Abby's uncle, and avatar of The Rot, Anton Arcane back into a portal to the Rot itself. Knowing their positions within the balance of the Red, Green and Rot, both Alec and Buddy agree that they must enter the portal to the Rot, and defeat it in order to reestablish the balance. Alec tethers a vine to a nearby tree, and jumps into the portal along with Buddy.
Soon after both Alec and Buddy enter the Rot, elsewhere, Cliff seemingly becomes possessed by the Rot, leaves his bed and continues to chant "Rotworld is coming" as he meets a dark, fly ridden figure on an empty road. At the portal to the Rot, Rotlings begin to pour out into the world, leaving Abby, Ellen and Maxine to battle them off, until Abby can close the portal around Alec's tether vine. In the Rot, while Alec and Buddy climb deeper into the barren world, Anton Arcane appears. He reveals that because of the Green being allowed to resurrect Alec into the Swamp Thing, the Rot was given it's chance to balance the scales and resurrect himself. He severs Alec's tether to the outside world, and sends the duo falling into the Rot, informing them that time moves differently in the Rot, them having been there for a year in their time, and they've already lost.
On the outside world, with Alec's tether being cut, both Abby and Socks fear for the worst. Their last ditch option would be to destroy the Parliament of Decay, but Socks claims that no one knows where they're located. Abby on the other hand, tells them that she knows, that she's always known, it has been inside her. Inside the Rot, both Alec and Buddy fall back into the real world in separate locations. The world is now a barren wasteland, but both can feel remnants of the Green and the Red. Where Buddy finds a zoo full of slaughtered animals, Alec is confronted by Poison Ivy, now one of the last warriors for the Green. Both in dire situations, they both realize that Arcane was telling the truth, and they have already lost.
Rotworld: Kingdom of the Green
When Alec Holland awakes, he is confronted by Poison Ivy and Deadman, who are skeptical as to who he truly is. Alec tells them who he is, and despite Ivy not trusting him, Deadman uses his powers to confirm that Alec is who he says. Confused, Alec is informed that the desolate state of the world is what happened after both he and Animal Man disappeared. Needing to speak with the Parliament of Trees, Ivy informs Alec that the Parliament has protected itself, suspended in a giant tree trunk, creating the last area on earth to have plant life, the Kingdom of the Green. Inside, Alec tries to get answers from the Parliament, and gains a deeper understanding of what happened. He asks what happened to Abby, but before he can learn of her fate, the Kingdom of the Green is attacked by the forces of the Rot, lead by the Rot possessed Teen Titans. As Alec, Ivy and Deadman struggle to fight off the Rot's forces, the Parliament debate on whether or not they should tell Alec that Abby had died shortly after he entered the Rot, in a plane crash caused by the forces of the Rot. After being rouged up by the Titans, Alec manages to use the Parliament's power, and grow his body to giant like size, easily crushing the Titans with one of his feet. Refusing to believe that Abby is dead, claiming he can faintly hear her, Alec and Deadman set out into the rotlands, in order to destroy Arcane, and find Abby. Their first stop is Gotham City, as Deadman had heard someone there had been working on a weapon to defeat the rot. They decide to take the water to Gotham, and while floating adrift, the two are attacked by William Arcane, who is in possession of Aquaman's trident, and a Rot infected Starro. Alec and Deadman are about to be eaten by Starro when Alec breaks them out killing Starro. William comes back with a another of his creatures, and it attacks Alec but Deadman possesses William killing himself and William also killing the monster saving Alec. Before Rotworld Abby is being held captive by Anton Arcane in his castle and he shows her the clones of her he made when he bit her when he tried to take her back to the Rot but was stopped by Alec but bit off part of her shoulder which he cloned from. Abby escapes and briefly stops Arcane and then destroys the clones. Abby tries to escape but is stopped by creatures of the Rot. Alec arrives in the Bat cave but is attacked by rot mutated Batman who after biting Alec is shot by Barbara Gordon who has been turned into a Man-bat by the Rot and saves Alec.
Barbara reveals Batman was infected retrieving the Man-Bat formula allowing her to have the powers of the Red and be immune to the Rot. Batman had been building a powerful weapon to defeat the rot prior to his infection, which is housed at Arkham Asylum, one of the few safe places on earth. He left a video message for Alec to finish it. At Arkham, he notices several guards, former bat villains Floronic Man, Killer Croc Mister Freeze, united against the threat of the rot, and finishes the weapon just as a rot infected Giganta leads an army to attack, with the threat of Rot Superman looming.
Rotworld: Kingdom of the Red
Waking up in a desolate San Diego, Buddy Baker doesn't have much time to gather his bearings, due to being attacked by a Rot infected Hawkman. Before he can be severely harmed, Buddy is saved by a group consisting of Black Orchid, Steel and Beast Boy. The trio of stranded heroes bring Buddy back to the Red's last stronghold, the Kingdom of the Red, a fortress that the Parliament of Limbs sacrificed their own bodies for to create. Inside, Buddy is confronted by John Constantine who informs him of the death of his family. Buddy can't believe what he's told, but as seen in a year ago, when his family goes searching for Cliff Baker, both he and his mother Ellen Baker are some of the first to become infected by the Rot. Back in the Kingdom fo the Red, it doesn't take Arcane's forces long to wage an attack on the newly discovered Buddy Baker. Rot infected versions of Hank Hall, Dawn Granger, Deathstroke and Grifter are all lead into an attack by Felix Faust who had willingly joined Arcane. Though the forces of the Rot are defeated, Faust tells Buddy that he was simply intending to deliver a message: "We have her," meaning Maxine. Despite knowing it is most likely a trap, Buddy feels if there's any chance of saving his daughter, he must take it. Buddy then leads Orchid, Beast Boy, Steel and Constantine into the Rotworlds, where they mistakenly wonder into New Gorilla City, and are discovered by Gorilla Grodd and his army.
Escaping, Buddy manages to recruit a new powerful ally in the Plant Green Lantern Medphyll after saving him from mad magical Blackbriar Thorn, as he encounters a rot infected Talon and Amethyst as they go to Rot central
Rotworld: Secrets of the Dead
Following Frankenstein and the Creature Commandos in Rotworld, this continues from #13 through to #15 in a three issue tie-in.