Frank Duffy, a reporter for a local newspaper in Miami, sneaks into a research laboratory that carries out experiments on animals.
Bitten by a rabid monkey, the young man falls prey to an uncontrollable fury and spreads the infection in the nearby college, where the carefree Halloween party taking place there turns into a bloodbath.
Lenzi "took the one [he] liked the most", "about a female scientist that has an accident in her lab and becomes genetically mutated, transforming into a tiger", and rewrote it, but by the time he arrived at the United States, he found that his backers wanted him to film the other script, which became Nightmare Beach (also known as Welcome to Spring Break).
: A 1980s Trash-Horror Odyssey of the film, "Primal Rage borrows the plot and general sense of chaos from George Romero's The Crazies, gives it a shot of Cro-Magnon idiocy, and adds a "Avoid the Noid!"
Leapfrogging over mundane hilarity (padding that involves racquetball), squirm-inducing gore (eyes ripped out) and the savoir fare of the late 80s (skull costumes from The Karate Kid), Primal Rage does not ask much from its audience.