Ghosthouse opens with what is perhaps the best and only truly shocking sequence of the movie, a prologue occurring in 1967 in which a little girl dressed in white named Henrietta (Kristen Fougerousse) is locked in the basement as punishment by her father. He promptly is killed with an ax in his head while his wife, the girl's mother, first loses an eye to an exploding mirror and then takes a knife in the neck.
Jumping forward to 1987 in Boston, we meet Paul (Greg Scott), a ham radio enthusiast, and his oddly unattractive and tiresome gal Martha (Lara Wendel, who once enjoyed limited popularity as an Eurotrash sex object in Italy due to her under-age nude scenes in Maladolescenza  and can also be seen in, among many others, Killing Birds [1988 / trailer], I frati rossi [1988 / trailer], Midnight Killer [1986 / trailer], Tenebre [1982 / trailer], Ring of Darkness [1979 / trailer] and The Perfume of the Lady in Black [1974 / trailer]). Paul gets some mysterious broadcasts over his radio and follows them back to a house somewhere in New England – according to some sources, the same house used by Lucio Fulci in Quella villa accanto al cimitero (1981 / trailer) – where they run into four other flunkies, one of whom also happens to be a ham radio enthusiast.* Despite recognizing the voices screaming in the death throes of terror as their own, everyone not only sticks around but also always find convenient reasons to wander away alone, even after one youth dies and "scary" things happen. At one point, Paul states "I feel like we're in some kind of danger and we got to do something"; what they decide to do is more or less systematically offer themselves as fodder to the ghostly Henrietta and the demonic doll she stole from Poltergeist (1982 / trailer).
Lenzi is never the best at creating appealing, engaging characters, and Ghosthouse is no exception. The males are all rather bland, none of the three featured girls are particularly likable, and all seem to be about as equally dense. How dense? Well, for example, the secondary final girl, Susan (dreamy-eyed Mary Sellers of StageFright: Aquarius [1987 / trailer] and The Crawlers [1993 / trailer]), actually decides to reenter the house to take a shower despite a previous death and a psycho on the loose; the other non-final girl Tina (Kate Silver in her only known film role) does likewise for no apparent reason other than spite. These and other such similar actions makes it seem doubtful that the combined intelligence of the characters would equal that of a fish, and the result is that the viewer soon begins to look forward to and even cheer their imminent demise.
But as fun as some of the characters depart (there is a fine guillotine scene for example) and as shocking as some of the visuals are (the head in the washer was nice) the various scenes and events seem more to be simply stitched together than to actually follow a connected and continuous plot. What's with the maggot face in a cloak with a knife? Who did Pepe (Willy M. Moon) blow to get his totally unnecessary part written into the film? Why the hell did the ham radio even pick up signal from the future in the first place? And what was the point of the crazed handyman named Valkos (Donald O'Brien of Zombie Holocaust [1980 / trailer] and dozens of other Eurotrash films of varying appeal), who runs around killing or injuring a person here and there for no real reason? One would think that the generic plot would offer room for a lot of action, but oddly enough the film comes across as slowwwww-moving and features way too much expository padding where it isn't needed and not enough where it is.
Ghosthouse / La Casa 3 is truly in no way, shape or form imperative viewing.
Despite its original title of La Casa 3, by the way, the film is very much a stand-alone film. The title was decided upon after the film was completed to cash in on the market value of the name "La Casa" (which translates in English into "The House"): Sam Rami's early classics Evil Dead (1981 / trailer) and Evil Dead II (1987 / trailer) were called, in Italy, La Casa and La Casa II, and when it came time to release this film the title La Casa III was chosen simply to ride on the coattails of the success of Rami's films. (Lamberto Bava's TV horror film The House of the Ogre [1988 / trailer], which was initially released as Demons III to ride on the success of Demons [1985 / trailer] and Demons II [1986 / trailer], was also at one point released on DVD as Ghosthouse 2 to ride on the "success" of this turkey.) The market value of the name "La Casa," however, seems to have dwindled in Italy, for after 1988's La Casa IV Witchcraft (aka Witchery – trailer) and La Casa 5 (1990 / trailer) the brand name seems to have been retired.
*Were/are there really "young" ham radio enthusiasts? I know no one now who even has one, and in my childhood days, it was only lonely old men who played around with them. I imagine even they have since moved into the cyberworld and now only chat.... preferably with nubiles, I assume.