A woman and her son are attacked by strange people, and they hire a private detective agency to protect them and learn why. Somehow, they can afford having the entire agency on their case, even having as many as three of them staying with them around the clock at times. The detectives aren't particularly good at anything except for being killed, which takes care of the problem of affording them all, I suppose.
Every once in a while, the movie remembers that there was a poorly-defined framing device at the beginning that made everything that followed a reminiscence rather than a current event. So, very occasionally, the lead actor will say something in voice-over ("that's when I first talked to you"), which is silly and totally unnecessary.
The acting in the movie is absolutely dreadful. Some of the actors are capable of acting; they've displayed some skill in other movies, but none of that is evident here. The little boy who is the center of the story is unappealing; as with many kids in 1970s Italian horror movies, to look at him is to want him to die. Thus, one's sympathies are with the cultists who want to kill him, even though they're scarcely appealing at all either.
The video box says the movie is rated R. How that could be possible, I can't imagine. A number of people are killed, but the violence is hardly even the equal of a television cop show, and not that of a horror movie. There is no nudity. There is little, if any bad language.