Three years on from the events in Hello Mary Lou: Prom Night Two (1987), demon bombshell Mary-Lou Maloney (Courtney Taylor) resides in hell, chained alongside a chorus line of scantily-clad cuties forced to dance endlessly to Fifties doo-wop music. No, really. Inevitably, Mary-Lou busts free and returns to haunt her old high school seducing teenager Alex Grey (Tim Conlon) who goes from lovable loser to cold shouldering his sweet girlfriend Sarah (Cynthia Preston). Thanks to Mary-Lou's evil intervention a hitherto hapless Alex excels on the football field and aces every one of his term papers. Unfortunately her help involves bumping off anyone that gets in Alex's way, whether jabbing an electric whisk through the throat of his chocolate-chomping chemistry teacher, acid-melting the face off his bitchy guidance counselor or impaling the school bully with a drillbit-topped football. At first Alex doesn't seem to mind. All he has to do to maintain this winning streak is bury a few bodies and enjoy amazing sex with his gorgeous new girlfriend. Gradually both his conscience and abiding love for Sarah get the better of him, but of course hell hath no fury like a demon woman scorned.
Few remember there was a third film in the Prom Night franchise although the saga carried on even further with the release of Prom Night Night IV: Deliver Us from Evil (1992) starring lovely Nicole de Boer of Cube (1997) and Star Trek: Deep Space Nine fame. Like that film Prom Night III went straight to video. Continuing the supernatural theme established in the second sequel the film seemingly takes its cue from the increasingly juvenile, rapidly deteriorating A Nightmare on Elm Street sequels as it strings together a load of cartoon-like, special effects driven set-pieces wherein Mary-Lou kills people in imaginative ways. Just like Freddy Krueger she has a fried face and deadly fingernails, a line in cheesy one-liners and adopts an array of outlandish guises: ice cream vendor, all-American housewife, prison guard, trash-talking hairdresser. Sherilyn Fenn look-alike Courtney Taylor lacks the striking otherworldly presence of original Mary-Lou (Lisa Schrage) but makes the role her own exhibiting a flair for campy comedy. She also performs a memorable striptease by the window while Alex struggles to bury her latest victim, after which the filmmakers intercut a sex scene with the disposal of the corpse. Yecch.
Unlike the previous sequel, this is much more certain about what it wants to be which is a kitsch comedy somewhat similar to a Hanna-Barbera cartoon but with extreme gore. Promoted to the co-director this time around, series screenwriter Ron Oliver goes all out for ghoulish gags with a retro-Fifties theme including jokey nods Dragnet, The Wild One (1953), vintage educational films, EC comics and Sandra Dee. Working alongside Scottish born producer Peter R. Simpson (in his only directing credit), Oliver proves a creative if not always consistent force behind the camera making use of wild angles, Sam Raimi-style dolly shots and maintaining a fast pace. A good few jokes hit their mark notably the news report that blames Alex's murder spree on "bad dietary habits, rock music and too many horror movies", the cop held hostage who attempts to strike up a conversation ("So this is your first kidnapping, huh?"), bizarre monologues from Alex's oddball best friend Shane (David Stratton) and frankly unhinged dad, and a running gag involving some surreal announcements over the campus radio ("Attention all girls on the weight-lifting team. The facial hair removal clinic is now open. Attendance is mandatory!"). Future sit-com regular Tim Conlon and especially Cynthia Preston prove more engaging protagonists than are common in such fare. Preston proved something of an Eighties horror favourite having acquitted herself admirably in cult Canadian efforts Pin (1988) and The Brain (1988). She proves especially winning at the lively finale where Sarah grabs a flamethrower and plunges straight into a retro-Fifties themed hell to confront the undead denizens of a zombie prom night along with a malevolent jukebox that shoots lethal vinyl. Although the downbeat ending seems at odds with the overall tone, Prom Night III still provides silly, imaginative fun.