If you haven't seen this film before, you've seen one like it. There is a lunatic at large, and he is driving an ice cream van. A young boy disappears and is believed drowned accidentally, although his body is not found. The police may believe this, and his parents, but his nanny knows better. Unfortunately she is the one the child's mother especially holds responsible because instead of watching her charge she'd been in a lengthy discussion/argument with her boyfriend who'd confessed to having it off with someone else.
Trying desperately to win her back he panders to her claims of foul play, the two find and break into the ice cream man's home, hoping to find what exactly? Then the bad guy reappears. To cut a long story short, he murders the boyfriend and kidnaps her. Well, it would have been a very short film if he'd murdered them both. Surprise, surprise, he is not simply a lunatic in the evil sense but delusional, because he thinks he can take her boyfriend's place.
That's about all you need to know. What happens next is fairly conventional but not totally predictable. What makes it so tedious is the long goodbye which is played out from the damsel's hospital bed. On the bright side, the soundtrack could have been a lot worse.