Earth’s water has been infected by a strange parasite called Rot Worms, a danger unleashed when eggs ride the rain across every corner of the globe. Once hatched, the worms feast on human flesh, turning their hosts into mindless zombies and pushing civilization toward a fragile edge.
The story centers on Fred, an elderly man who navigates a ruined city with a walker he wields like a weapon. He’s quirky, stubborn, and certain that his walker speaks to him as he wanders in search of a new pair of shoes. His quest leads him into a mall where a recently bitten nurse becomes a zombie in moments, forcing him to crash through chaos and flee for his life.
Outside, a skilled shooter named Jon steps in to help Fred escape the expanding nightmare. In the chaos, Fred loses his walker to the nurse’s onslaught and ends up stealing a motorcycle to keep moving. The ride is perilous: the bike runs dry on a bridge while legions of the undead close in from both sides. Yet Fred earns back his walker and mows through a wave of zombies, unable to finish off the nurse who set this chase in motion.
Along the route, Fred rescues another survivor—a weary old man clutching a bottle of prune juice. The man, however, bolts away rather than joining Fred’s fragile escape. Seeking rest, Fred sits on a park bench and pores over a newspaper that unveils a chilling new parasite: Brain Worms, which prey on the brain, erase memories, accelerate aging, trigger hallucinations, and drown the host in voices. It’s a grim echo of Fred’s own condition, for the blood from his bridge confrontation still carries Rot Worms that threaten to overpower any weaker infection.
The next day, Fred’s friend Jon realizes the truth—he has already fallen prey to a Brain Worm. Jon attempts to kill Fred, but the two are overwhelmed by zombies, and Jon is doomed.
Eight days pass and a new band of survivors—Benjamin with his two sons and another man named Larry—drive through the city in a van, hauling supplies and looking for Benjamin’s wife. The group loses members along the way: Larry is attacked by the undead and accidentally shot by one of the sons. It’s revealed that the nurse Fred met earlier is Benjamin’s wife, who left the group to help others but has become a zombie herself. Benjamin’s attempt to pull her back turns fatal as a second zombie decapitates his wife.
Meanwhile, a man named Hac is sent by his bitten friend Mac to find an antidote. Mac believes the old man’s prune juice bottle holds the cure. Both Hac and Mac die before learning the truth, but their suspicion proves accurate: the bottle contains an antidote called “Zombifate,” which the old man constantly consumes. In a parallel thread, three soldiers who call themselves the Sanitation crew drive a bus to herd the zombies, using the undead as cover as they kill the infected one by one. Fred witnesses their brutal tactics and nearly crosses paths with a lone soldier before the ambush by more zombies forces him to flee again.
The old man eventually catches up with Fred and urges him to resist the worms’ influence. For a moment, Fred seems to regain control and saves the old man from a fresh wave of zombies, but his ally dies of a heart attack soon after. Desperate, Fred tries to cure himself with Zombifate, only to have the worm inside him resist. In a grisly turn, Fred feeds on the old man’s flesh, and the antidote inside the bottle triggers a strange reversal: the Zombifate swamps the Rot Worms, forcing them out of Fred and ultimately allowing him to survive and regain a footing in a safer place (hinted at in a City of Rott 2 preview).
After the credits, a man who has trapped himself inside a box laughs about surviving the apocalypse—only to reveal he is also infected by a Brain Worm.
Key themes and tone: a post-apocalyptic survival tale that fuses bleak danger with grim humor, as a lone elder wanderer clings to humanity through bizarre rituals, odd companionship, and a desperate search for a cure that may never come. The film blends claustrophobic chase sequences with quiet, character-driven moments, portraying how memory, loyalty, and stubborn resilience are tested when a city is overrun by parasitic threats that target both body and mind.
