When the film begins, Sheila (Leslie Ann Warren) is telling her old boyfriend, Russ (Ryan O'Neil), that she's met someone she loves...and the old boyfriend accepts this like a stand-up guy. However, when he meets the new boyfriend, Leo (Peter Haskell), he's attacked and nearly beaten to death by the super-controlling new boyfriend. Needless to say, Sheila's love for Leo is gone...but Leo isn't. He soon begins stalking Sheila and threatening her...and he clearly tells her that she WILL marry him! Talk about a horrible ex-boyfriend! This guy obviously is mentally imbalanced and dangerous...but folks don't seem all that worried about him. The old boyfriend, Sheila and her father all have witnessed his clearly illegal behaviors...but they are hesitant to press charges though God only knows why. And, even when Sheila marries Russ, he continues to stalk her...yet folks don't seem to take this maniac seriously. Even when he shows up in the other side of the country where Sheila now lives, the couple are remarkably unworried about this! Obviously they'll end up regretting this by the end of the film--even after they move across the country to get away from him!
The summary on IMDb calls Leo a 'psychotic' but that is not quite right for folks like this in real life. Leo's complete lack of conscience and violent tendencies would clearly qualify him as an Antisocial Personality (frequently called a 'Sociopath') as well as a Erotomania (a stalker). These are more recent psychological terms but are much more appropriate given his behaviors...at least up until the end of the movie. Making him a psychotic at the very end makes him seem rare or legally incompetent...but sadly violent stalkers like this are amazingly common and know exactly what they're doing.
So is the film any good? Well, it does draw attention to creeps like Leo--so it is a good public service sort of picture. While the story is a bit extreme, it does illustrate how many of these folks behave. Unfortunately, the film also is a bit silly and poorly written at times, such as the folks refusing to talk to the police until the very end. And, the finale...wow...it went for sensationalism more than providing a meaningful ending. Overall, a very mixed bag--a great idea but not executed especially well. Plus the ending pretty much undoes the good in the film up until then.
By the way, beware of the opening song....it is hellishly awful. Resist the impulse to change the channel or throw objects at your television. Or, just hit the MUTE button!