Aerobics instructor Christie (Lucinda Dickey) becomes possessed by the evil spirit of a fallen ninja warrior. This spirit seeks revenge on those who killed him, controlling Christie's body to carry out his vengeance. The only way the spirit will leave her body is with the help of another ninja.
The ground NINJA III covers cannot be predicted as it opens on a ninja's final corporeal moments on a golf course in broad daylight, in a sequence that must be seen to be believed! On top of ghostly possession directly exploited from EXORCIST fame, it also tries to cash in on the success of FLASHDANCE and its ilk with gratuitous aerobics sequences, a love interest with a cop who sports one of the hairiest bodies in the history of contemporary cinema (whom Christie seduces by pouring V8 on - yes, you read that correctly), and a revenge story that about buckles under the weight of everything stuffed into it.