And Soon the Darkness (1970) 3.5 of 4

mostly synopsis: 
Two English girls, brunette Jane (Pamela Franklin) and blonde Cathy, are bicycling through the French countryside. True to type, Jane wants to stick to the plan and is happy just seeing the countryside, while impulsive Cathy is bored and wants some excitement. These differences boil over into an argument, and the girls split up, with Cathy sunning herself by the roadside while Jane pedals on. Probably thinking of the tall, "dishy" Frenchman they noticed at a cafe, Cathy hangs up her underwear on the trees, as if drying them. Later, she takes them down, creeped out by the silence, feeling watched. Meanwhile, Jane cools down and circles back, but is unable to find her friend. She does find Paul, the Frenchman, and he helps her look. Paul ultimately claims to be law enforcement, based in Paris and on a working holiday. He's curious about the murder of a pretty girl in the vicinity several years back, unsolved. Jane had also heard about this murder from a local, middle-aged couple, the LaSalles. Mrs. Lasalle tried to warn Jane away, despite the language barrier. This film expertly ratchets up the suspense -- like Jane, we suspect there's a killer of women on the prowl, but who is it? Is it Paul, handsome but temperamental? Is it a local, like the grouchy Mr. LaSalle? Two other suspects present themselves: a man deaf since the war, and an oddball too, and finally the local constable who shows up to help. Jane becomes more and more sure it's Paul who's the killer. He acted strange when they encountered him, following them but not speaking. He's presented no evidence that he's with law enforcement. Jane barricades herself in the deaf man's rural house, and must remain very silent when Paul tries to get in. Paul then does get in, smashing a window, but Jane eludes him, even when she's shocked by the discovery of Cathy in the closet -- Cathy's corpse, that is. Finally, Paul spots Jane outside, chases her. Jane eludes him, then hides behind a tree; when Paul approaches, she smashes him with a rock repeatedly, and he collapses. Relieved, Jane runs to the constable, embraces him. He holds her, but then his hand wanders down, across her butt and into her back pocket: he's the killer! He starts to assault Jane, but Paul lurches into the frame and shoots the constable. Jane is safe, we assume. We see two more young women bicycle into the region, sure of a pleasant holiday ...

mostly review:
This is a very tight little thriller; some might call it a Hitchcock imitation, but it's a fine one. My only complaint is that the score is too much at times, too melodramatic for such a spare, merciless little film. The score indicates someone didn't quite have faith in the film. Still, this is a must see for horror and thriller buffs. For me, it succeeded brilliantly at keeping me in suspense and at using red herrings to put me in Jane's shoes: I did not know who the killer was. As with John Carpenter's Someone's Watching Me!, the protagonist is a woman surrounded by men, and she has no idea whom to trust. These films communicate something about what it's like to be female. And Soon the Darkness deserves to be better known; I'd class it with other cult films of the era: Carpenter's, Spielberg's Duel, and Richard Franklin's Road Games. As such, it's also a stepping-stone toward Mad Max and imitators.
It was directed by Robert Fuest and co-written by Brian Clemens, both of whom are known for the U.K. series The Avengers. Fuest also directed the Dr. Phibes movies, with Vincent Price; this film lacks the tongue-in-cheek quality you might expect. Clemens was in his prime, soon to have his own TV series, Thriller, and to write another cult film shot mostly outdoors, Captain Kronos Vampire Hunter. His writing partner on this film was Terry Nation, the driving force behind much of the best U.K. televised science fiction of the 1960s through the early 1980s.
 The Hitchcockian touches include close-ups of ordinary object (such as Cathy's portable radio); the wide, charged framing of shots of the country fields, reminiscent of North by Northwest; the games with identity, and Jane's confusion over whom to fear; and the mixture of sexuality and misogyny that motivates the killer. Made in 1970, by and for a younger generation, the film goes a bit further than most of Hitchcock: Cathy is frankly randy, and Jane throws up, although daintily off-screen.
The film was shot mostly on location, and it's beautiful to look at. Cute Pamela Franklin seems to have a cult following based largely on this performance. She's an early final girl. This film was far ahead of its time in wedding rural horror (fear of throwbacks or weirdos out in the sticks) to a sort of pre-slasher plot (although the killer seemingly doesn't use blades). If it had been remade in 1990 or 2000, that might have caused a stir, but the eventual 2010 remake, which I haven't seen, was probably behind the curve, following such fundamentally similar, if more graphic films as High Tension, Eden Lake, and many others.