Diabolique is a 1955 mystery movie that is French, and while it isn't horror it does have some terrifying scenes, and a very well written plot. I will admit that these days the plot seems predictable though. I already knew the ending way before the last hour was even arriving. The movie doesn't lose it's entertaining value though. The acting is good and some parts do have a terrifying look to them that you can't help but watch. I wouldn't watch it in the dark again for sure.
Summary: Christina is the wife of a mean headmaster, Michel. With the help of his mistress, Nicole, they devise a plan to kill him. After they murder him, and dump his body into a pool he mysteriously disappears, and leaves the both worried about where his body will turn up. When his body is instead being seen around the campus they teach at they both worry that perhaps they were wrong in the assumption they killed him.
