During school break, they lure him away from the school, where they drug him then drown him in a bathtub. Next step is to sneak him back to the school and drop him into the disgusting pool. After a few days, his body should surface and his death be ruled an accidental drowning.
But, when the body fails to surface, the pool is drained and the body is gone.
Strange things happen while our two heroes try to figure out what happened. Watch the movie if you want to find out what happened.
At first I thought the blond (Simone Signoret) was the wife and the brunette (Vera Clouzot) was the girlfriend. Vera looked younger and prettier than Simone. Vera was, in fact, almost ten years older than Simone. And, incidentally, the wife of the director. She would die only five years later causing her husband to sink into depression.
The ending of this movie is a bit of a surprise and I am very annoyed to say that most of it was ruined when I watched the 100 Years of Horror documentary. Apparently they missed the anti-spoiler message. They didn't ruin the end of any other movie. Damn you, Count Dooku.
The French title was "Les Diaboliques", meaning The Devils, apparently referring to the plotting women. The American title becomes singular, I presume referring to the headmaster, who was truly horrible. And interesting shift in emphasis, if that's what it was.
The mood, the acting, the pacing, the story: everything was just about perfect. Had the ending not been spoiled, I would have enjoyed it even more. The surprise ending makes a second viewing less interesting, but I don't care. AMRU 4.