There are enough intriguing twists throughout Nightkill, that on the basis of these revelations alone, the film rests as a solidly entertaining thriller. But what distinguishes this underseen 1980 feature as something uncommonly and increasingly interesting, is its effortless integration of strangeness into a fundamental suspense structure. Its oddities aren’t surreal or wholly removed from the plot, as obvious diversions or self-conscious distractions, but are seamlessly, subtly worked under the skin, contributing to the picture’s unsettling atmospheric tension.

As entire scenes, single actions, or as seemingly incongruous plot points, so many of these moments are implemented without comment or further initial development. And they’re evident at the very start, when, for example, the distorted voices of lovers Katherine Atwell (Jaclyn Smith) and Steve Fulton (James Franciscus) are heard in some stifled bedroom chatter. They are, as it turns out, being recorded by an unseen party. This secretive eavesdropping trope is itself fairly standard in the annals of the erotic thriller (though Nightkill is far less erotic than its poster image implies), but the warped voices here and the lack of instant reasoning—considerable time passes before we discover who is listening—initiates a shaded ominousness that envelops the duration of the picture.

Triggered by the editing and the narrative flow, the ensuing minutes suggest the recording is the work of Wendell Atwell (Mike Connors), Kathy’s husband, who enters the picture at an airport, tucking away a stash of cash in a locker and paying off a guard. Even then, his own immediate activities are impenetrable and portentous, and as Nightkill expands, presenting a wider view of this central trio in their combative element, mysterious motives are augmented by the disquieting isolation of the film’s desert setting, primarily a remote mountaintop home outside Phoenix, Arizona.

There may be some variability when it comes to this desert city—alongside industry and contemporary affluence, it’s often presented as a Western town still in flux, with ten-gallon hats, turquoise jewelry, and bolo ties, iconic remnants of its cowboy past—but there is no doubt about the state of the Atwell marriage. The acrimony between Katherine and Wendell is bitter and forceful. “You get nothing,” he tells her, “cause you’re worth nothing.” It’s clear one of them is likely to get killed (what isn’t clear is how it hasn’t happened already). Wendell is ruthless, wealthy, and his biological business causes some toxic concern, which he indifferently dismisses. The accessibility granted by his occupation plays a minor part in Nightkill, but it isn’t entirely relevant.

It is, instead, one of those anomalous components that are peppered throughout the picture, as a little subtle something to lend the film a stifling air of instability. There are other details, too, like the omnipresent threat of the Atwell family Doberman, always on guard, or a side character who pours “antiseptic” champagne over a bleeding dog bite (testifying to his cavalier eccentricity and the pet’s potency). Complimenting Wendall’s shadowy vocation in biological defense is Steve’s CIA involvement, alluded to but, again, never fully advanced. These are similarly peculiar ingredients that all lend Nightkill a dash of unease, which only intensifies the film’s enigmatic essentials.

Part of Nightkill’s swift impact has to do with Joan Andre’s screenplay, based on a story by John Case, which drops the viewer in the midst of a pre-existing strain. We at once know more than the characters do, witnessing their independent behavior, and yet we know far less about their motivations and intentions. This ongoing anxiety is then heightened by Günther Fischer’s haunting, spurring score, like lingering white noise, and the expressive histrionics of the film’s principal cast, particularly Smith, who gets put through the emotional ringer.

Andre’s storyline proceeds beneath an oppressive cloud of entrapment and severe paranoia, underscored by body disposals, stalled cars, and tell-tale evidence, and when it becomes apparent how far these characters are willing to go—the ostensibly decent Steve makes his move with chilling nonchalance and autonomy—the aftermath is inherently volatile. Some of the subsequent developments are rather predictable in hindsight, including one shock spoilt by a slow-motion, soft-focus delivery, but such is the engrossing nature of Nightkill that even these instances of relative orthodoxy are successfully accomplished as the film is playing out.

Left to contend with the onslaught is Katherine, a hapless magnet for sleaze: Steve and Wendell, but also a lawyer played by Fritz Weaver, whose philandering raises the threatening ire of his wife (Sybil Danning). Ultimately, the psychological torment Katherine endures swells into a delirious breakdown, a night of dread and violence. In an interview included as part of the new Kino Lorber Blu-ray of Nightkill, Smith recalls her Charlie’s Angels past and her preparation for this demanding and altogether distinct role, which she enacts with laudable enthusiasm.

She also discusses the film’s fourth primary player, and the only actor whose credit is encased in a rectangle (for some reason): the legendary, laid-back Robert Mitchum. Appearing as detective Lt. Donne, who suspiciously stumbles into the discord, Mitchum’s dual purpose is to impart the conviction of the observant cop, contributing another layer of apprehension, and to evoke with the weight of his star stature a concealed prominence in his precipitous presence.

Smith also sings the praises of Nightkill director Ted Post, as do Howard S. Berger and Nathaniel Thompson in their adoring, enlightening commentary. Smith says Post made it a point to bring on a strong director of photography to shape the visuals of Nightkill (Anthony B. Richmond, who shot Nicolas Roeg’s Don’t Look Now and The Man Who Fell to Earth, from 1973 and 1976, respectively), allowing him to concentrate on the performances; the tactic worked well in both regards. Nevertheless, though having directed popular titles like Hang ‘em High (1968) and Beneath the Planet of the Apes (1970), Post was generally known for his extensive television work, a secondary grade that didn’t help Nightkill’s notoriety when the film itself failed to receive a theatrical run in the United States and was relegated to a television release.

It was an unfortunate demotion, for Nightkill is considerably more impressive than this throwaway standing suggests. While admittedly accurate, it’s also unfair for the film to be known solely by its cinematic parallels (it’s like a Clouzot-Hitchcock-Coen hybrid), and not for its own unique qualities. It’s also a shame it was limited by a misleadingly sordid marketing campaign, which sold the picture as a facile slasher. All of this said, though, if referential name dropping gets people to see Nightkill, and if an exploitation promotion piques some interest, so much the better—whatever it takes to put this noteworthy feature back in the public’s eye.