Freddy (Thom Mathews) is working his new job at a medical supply warehouse. His co-worker Frank (James Karen) shows him some cannisters in the basement that have bodies in them.
The bodies have been infected by a gas that turned them into zombies back in the 1960s. The government had stopped and covered up the incident but the containers got lost and ended up at the warehouse.
Frank accidentally cracks one of the containers and both Freddy and Frank are gassed. A cavader comes back to life and destroying the brain doesn’t kill them.
Frank calls his boss Burt (Clu Gulager) and Burt helps clean up and takes the cadaver over to his friend Ernie’s (Don Calfa) crematorium.
Frank and Freddy are sick and getting worse. They burn the reanimated cadaver and the burning releases the gas into the atmosphere causing it to rain and the rain soaks the local cemetery and reanimates all the dead.
Meanwhile Freddy’s girlfriend and their friends have been hanging out in the cemetery and the zombies chase them into the warehouse.
Writer/producer John Russo helped co-write and produce George Romero’s classic Night of the Living Dead. Russo and Romero parted ways soon after and each retained partial rights to future sequels. Romero went and made Dawn of the Dead. Russo wrote his own sequel in 1977 called The Return of the Living Dead which was published as a book. Russo went to make it into a movie and had hired Tobe Hooper to direct. Hooper left the film and screenwriter Dan O’Bannon was given the directing job. O’Bannon rewrote the entire script not want to rip off Romero and made the film less serious and more of a black comedy.
The movie introduced the running zombies as well as the concept that zombies eat brains.