Country Justice begins with an unnamed Hick observing a river slowly being tainted with a line of green ooze originating from a nearby pipeline. The next day, Steve Earl, a Redneck living in the fictional valley of Yahoo, is confronted by his wife (and sister) about the mysterious disappearance of their goat, Dixie. She hypothesizes that their goat was kidnapped by the Hatfield brothers, who have a strong disdain for both Earl and his wife. Earl sets out to find his goat.

Noticing his truck's key has gone missing, he stops by his friend Skeeter's house to find them. Along the way, Earl must fend off against zombies and mutant animals. He reaches Skeeter's house and finds his keys shortly after having to deal with Skeeter's incoherent rambling. Earl heads over to the Hatfield's farm, which is being overwhelmed by zombies. After the Hatfields' are dead, Earl raids their farm only to find Dixie absent. After leaving the barn, he finds his truck missing and is approached by Sheriff Cletus. After getting back into his car, Earl is told to go through a nearby nuclear power plant.

Going through the powerplant leads Earl to a town where he's locked up by a police officer, in order to keep him from being infected. He escapes prison shortly afterward and steals a boat that the officer tipped him off to. Earl then proceeds to go to a facility described by the officer, in which he fights against zombie security guards plaguing the facility. Eventually, Earl is led to a room where he finds a mad scientist using Dixie to make himself invincible. Earl quickly foils his plan, killing the scientist before rescuing Dixie. Earl then returns home with Dixie to his wife, elated that he finally found their goat.

After exiting his trailer, Earl is met by three lines of text that are bunched together in a way that makes them difficult to read. The following (as displayed in the screenshot) reads: "Congratulations Steve! You saved Yahoo country from the mad scientist! You are now invulnerable!".