I know I’m behind on my backlog, but it’s tough for me to find any interest in the wide releases that are out right now. I need something new. Something off the beaten path. Something shocking.

Well, I sure as hell got more than I bargained for this time.

Bone Lake certainly has a provocative title for an erotic thriller, but there’s more going on beneath the obvious. The film is set by a lake that’s so called because the original property owners inexplicably found layers of unidentified human remains washed ashore. The title’s double meaning makes it a perfect fit for this particular movie. And of course that cheery backstory makes it a perfect spot for a rental vacation home.

We open with Diego and Sage, respectively played by Marco Pigossi and Maddie Hasson. Diego is a community college teacher who wants to quit his job and be a full-time novelist, despite some well-founded fears that he may only be a mediocre writer. This leaves Sage supporting the both of them financially, as she recently left her freelance journalist job to take a promotion and work in editing.

I might add that they’ve been dating for three years and Diego spent all their money on this weekend getaway so he could propose. Sound like a bad idea? We’re just getting started.

Enter Will and Cin, respectively played by Alex Roe and Andra Nechita. They’re another couple who accidentally booked the exact same house for the exact same weekend. Naturally, the two couples do the civil thing and agree that the house is big enough for all of them. They get along well until they don’t.

Let’s sum up. What we’ve got here is a milquetoast couple — namely Diego (Asshole!) and Sage (Slut!) — who get themselves stuck in a middle-of-nowhere mansion with sexually charged maniacs hell-bent on corrupting them for their own amusement. You might call the Rocky Horror comparison forced, but I find it amusing all the same. Anyway, in terms of tone and theme, there is some slight connective tissue there.

This is an erotic thriller, so of course there’s sexual tension between the buttoned-up couple and the more impulsive pair of exhibitionists. The kicker here is that right at the open, we’re shown that Diego and Sage are having bedroom problems, to the point where Sage is faking her orgasms just to humor him. What’s worse, while Sage wants to try improving things with toys, Diego feels he should be enough for her without any help. Oh, and did I mention that Sage cheated on Diego back when they were just starting to date?

The bottom line is that Diego has crippling insecurity about himself as a lover, a writer, a potential husband, and a man in general. These insecurities exist in a rotten feedback loop with Sage’s unmet needs in terms of sexual satisfaction and financial support. Thus the both of them are easy prey for the raw animal magnetism and fearless charisma of Will and Cin. We’re watching these two couples befriend each other and tear each other apart in a way that’s deeply engaging to watch.

To be sure, the nuanced portrayals and effortless chemistry of the actors are a key reason why the film works as well as it does. I need hardly add that with a four-person cast in a movie where every last muscular twitch could be relevant, there’s no room for weakness. But honestly, the real powerhouse here is director Mercedes Bryce Morgan.

For one thing, genuinely good erotic thrillers are few and far between. Paul Verhoeven might be the only filmmaker I’ve seen who could work in the genre consistently well (and even he’s had some noteworthy failures). Still, Morgan clearly understood a key reason behind Verhoeven’s success: Lean into the trashiness. Don’t be afraid to make the characters unsympathetic. Go big and make no apologies.

That said, Morgan tempers that same over-the-top sensibility with a Hitchcockian sense of timing. She’s surprisingly good at knowing how long to hold a shot and precisely when to cut away. It’s diabolically crafty how the film will withhold just enough information, leaving just enough offscreen that we never learn what really happened or which characters can be trusted.

Even better, that same deft touch elevates the sexual content into something far greater than mere pornography. For an erotic thriller, I was surprised to see little actual nudity in the movie. Pretty much all we ever get is in the opening scene, and in a nightmarishly unsexy context. Through pretty much the entire movie, whenever the characters are having sex or in some state of undress, everything is positioned and edited in just such a way that the film playfully teases without ever actually showing anything. And it’s done in such a way that it somehow makes the film even more erotic while also ramping up the tension. Stellar work.

But then comes the third act. That bloody, bonkers third act. Bringing in the big reveal without throwing everything off the rails was always going to be a challenge, and I’m not 100 percent sure the film pulled it off.

I get what the film was going for: Putting our characters in a position where their relationships would be tested, such that they could only survive if they loved and trusted and intimately knew their partners. It’s a fine idea in theory. In practice, it’s something else entirely.

While I applaud the film for going big and over-the-top in every other regard, this is one time when the filmmakers probably should’ve scaled back and gone for nuance. This is a movie powered by complex interpersonal relationships, multiple layers of pathos, and plans within plans of mental/emotional manipulation. And the whole plot was powered by a cartoonishly one-dimensional homicidal psychopath. When the antagonist turns out to be some wild-eyed grinning psychopath with a ludicrous backstory and a nonsense motivation, it takes away from all the depth and complexity of the entire preceding film.

That said, the third act is also when the film switches genres and becomes a full-on slasher flick. The sudden switch in tone and genre is jarring, but at least it’s fun to watch. Unfortunately, while the kills are outright awesome in theory, they’re obscured or offscreen entirely in the finished product (likely due to budget constraints). The kills are still fun, to be sure, but nowhere near as graphic as the filmmakers likely intended.

I’m having a rough time grading Bone Lake. The intended themes don’t really land and the plot falls apart, both as a direct result of that third-act reveal and the genre switch. But for those first two acts — and even through the third act, to a lesser extent — the character drama was engaging and the suspense was masterfully executed. The movie was fun throughout, but watching the characters manipulate and outmaneuver each other is a very different kind of fun than watching them try to literally kill each other.

What it all comes back to is that I wanted some counter-programming that delivered something new and surprising. Something more memorable than The Smashing Machine or freaking Tron: Ares. If that’s what you’re looking for, go see Good Boy. But if that’s not available (or if you’ve still got some time left over, after watching a 70-minute movie), Bone Lake will definitely fit the bill.