Detectives Roger Mortis (Treat Williams) and Doug Bigelow (Joe Piscopo) are called to the scene of a rather violent jewelry store robbery. The robbers take on a squadron of police in a messy shootout, but neither seem affected when they are riddled with bullets. Thanks to the combined, albeit extreme measures of Mortis and Bigelow, they are able to take out the criminals, their acts narrowly avoiding termination. Meanwhile, a coroner friend of Roger's, Rebecca (Clare Kirkconnell) informs the detectives that the two bodies they had brought in had previously been to the morgue: not only do they have autopsy scars, but she herself clearly remembers performing the autopsy and has pictures to prove it, suggesting they simply got up and left the morgue at their own volition.
There is a preservative chemical compound found in the bodies that connect the pair of detectives to a company that had ordered a great amount of it recently. Mortis and Bigelow investigate and meet the company's head public relations person, Randi James (Lindsay Frost) who gives them a tour of the facility. When Doug wanders off to investigate a suspicious room, he encounters the reanimated corpse of a biker on a strange machine and in the fray, Roger is knocked into a decompression room used to humanely kill failed test animals and is asphyxiated to death.
Encountering the machine, and realizing it is capable of bringing people back from the dead, Rebecca and Doug successfully bring Roger back from the dead. He says he feels fine, yet he has no heart beat and his skin is cold to the touch, Rebecca surmises he has about twelve hours before the reanimation process ends and he dissolves into a puddle of mush. Roger decides to take this time to find and exact his vengeance on the person who killed him. They go to Randi's house just shortly before she is attacked by two more undead thugs, which the partners are able to subdue. Randi says that she is the daughter of a rich industrialist, and the owner of the company she works for until his death, Arthur P. Laudermilk (Vincent Price).
The two of them pay another visit to Rebecca, who says that she might have found a way to keep Roger in healthy condition indefinitely, but the unsure nature of the theory has him decide to spend his final hours finding the man who killed him. He and Randi pay a visit to Laudermilk's tomb and Randi admits she's not his daughter, more a protégé or daughter he'd never had. While there, they encounter a numeric code, which Roger discovers later is a vital clue. Upon returning to Randi's home, they find Doug dead, having been suspended and drowned in a fish tank for some time. Randi tells Roger that she too is undead, having been one of Laudermilk's first test subjects for resurrection, shortly before abruptly dissolving while asking for Roger's forgiveness.
Roger confronts the head coroner Dr. Ernest McNab (Darren McGavin) who was indicated by the secret numeric code that Roger had found, but he turns the tables on Roger, capturing him, then locking him in an ambulance with Rebecca's dead body in order to wait out his last hour to dissolution. He releases the brakes on the ambulance and puts it in neutral, sending it careening down the highway into a massive collision, from which he emerges, even more zombified and scarred almost beyond recognition. He returns to the hospital where McNab and a resurrected Laudermilk are pitching the resurrection machine to a group of very rich clients. Mortis breaks in and the ensuing crossfire between him and McNab's men kill off most of the rich clients, leaving Laudermilk cowering in a corner.
McNab reveals a test subject; Doug, resurrected from the machine. But because he's been dead for hours, the brain deterioration leaves him little more than an obedient zombie with no memory of who Roger is. Before he can obey McNab's orders to kill Mortis however, Roger manages to trigger Doug's short term memory and bring him back to normal. The pair go after McNab who immediately kills himself before they can do anything. Roger and Doug put McNab onto the resurrection table and resurrect him, but Doug starts the resurrection process again and it overloads, causing a screaming McNab to explode in the machine. Despite Laudermilk's pleas and promises of eternal life, the pair then destroy the machine completely, leaving the room pondering about the afterlife and reincarnation; Doug's fond wish of being reincarnated as a girl's bicycle seat intriguing the both of them. Roger says finally, "This could be the end of a beautiful friendship."Treat Williams as Roger Mortis
Joe Piscopo as Doug Bigelow
Lindsay Frost as Randi James
Darren McGavin as Doctor Ernest McNab
Vincent Price as Arthur P. Loudermilk
Clare Kirkconnell as Doctor Rebecca Smythers
Keye Luke as Mr. Thule
Robert Picardo as Lieutenant Herzog
Mel Stewart as Captain Mayberry
Professor Toru Tanaka as Butcher
Martha Quinn as Newscaster
Shane Black as Patrolman
Beth Toussaint as Lab Technician
Gene LeBell as Guard (uncredited)
Dick Miller as Cemetery Security Guard (uncredited)
Linnea Quigley as Zombie Go-Go Girl (uncredited)
The movie gained a negative reception, earning a Rotten Tomatoes approval rating of 14%. However, it has become a cult movie among fans of B-films and horror-comedy films.