Twenty-two year old Elise (Britt Ekland) has just gotten married to Paul (Hardy Krüger), a man almost twenty years her senior, and has moved in to his country house out in the rural landscape of Northern Spain. Waiting for him to join her, she thinks she is alone in the place as she refreshes herself with a bottle of pop, but out of the corner of her eye she suddenly notices she is being watched. This is Paul's twelve year old son Marcus (Mark Lester), who claims to have been allowed home a week early from boarding school in England thanks to a chickenpox outbreak - but that's not true...
It was Bad Seed time again, a theme that the movies have returned to on occasion, but rarely with satisfying results, with the original fifties item that kicked off the whole strain of such dubious entertainments looking camper than Christmas nowadays, and possibly did then as well. In this case, camp was not the problem, or indeed the saving grace, because what Night Hair Child most looked like was an idea for a horror movie that nobody involved had the slightest inkling of how to make successful. Obviously the film was completed, and people went to see it, so it gained success on that level, yet artistically this was all over the place.
What to do when your villain is a twelve year old sexual deviant and possible murderer? According to this, start by pussyfooting around such controversial plot points even though we can tell from the time that Lester, best known then, and now, for the title role in Oliver!, makes his entrance that the boy ain't right. What the actual opening scene of this is features a naked woman who we later discover is Marcus's mother, gaily climbing into a bath (if it's possible to gaily climb into a bath - she has a damn good try), turning on the heater and promptly getting electrocuted. Now, you don't begin your movie like that without a whiff of foul play, which is precisely what we are led to suspect.
Did Marcus do away with his mother? If he did, what were his reasons? Not one of the four screenwriters seem to have thought this one through, he's just bad because, um, because the story needed a bad guy and the conventions of horror invited the character of a young psychopath to the table. Needless to say, Lester, never the most convincing of child actors, is way out of his depth here and you're never able to accept that he could be the twisted mastermind behind the crimes Marcus is meant to have committed. The film tries to use that to his advantage as Elise (Ekland is similarly out of her comfort zone here) suspects something fishy is going on and Marcus looks like butter wouldn't melt in his mouth.
Except that she goes to visit his headmaster (Harry Andrews) and he lets her know what was the real reason for the expulsion: the little guy is a pervert who liked to spy on people in the surrounding area for kicks. Could it be that he has brought these leanings home with him and is spying on Elise and Paul in the bedroom? Turns out these are the least of her worries as although she persuades Marcus to admit that he murdered his mother (and pets), the method she uses - stripping off in front of him in exchange for information, not the conventional method of grilling a suspect - ends up with the finger of suspicion pointing at her. The film ends with psychiatrist Lilli Palmer quizzing Elise about her apparently unhinged ways, she can't get anyone to believe her about Marcus because they think she's bonkers, and a dream sequence of questionable taste ensues. Fin. Apart from Elise getting her own back, that is. A prime example of the "what were they thinking?" style of cinema. Music by Stelvio Cipriani.