The horror-comedy can be tricky to pull off. But when it’s done right, it can deliver shocking results. In the haunted-house-sex-farce “Happily,” a whole lot of shocks are crammed into one neat package, arriving like an anniversary present with a dark secret.

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The idea for the film came from writer-director BenDavid Grabinski, a screenwriter best known for his genre mashups (“Skiptrace,” “Cost of Living“). His love for rom-coms and horror is the inspiration for “Happily,” but he also wanted to direct something that would make us think. So he put together a “Twilight Zone” for married couples, with a whole lot of sex thrown in for good measure.

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It’s safe to say he strikes a unique balance, never settling on one genre, each element flirting with the others. The film is for those of us who get as much pleasure out of a steamy, rock-the-bed romance as we do watching a businessman get murdered with a wooden block. It’s for those of us who want something different.

When we first meet Tom (Joel McHale) and Janet (Kerry Bishe), it’s clear they are different from other married couples. They have sex everywhere, and I mean everywhere: in the kitchen, in the hallway, in the pantry. In their friend’s bathroom at a party, they nearly cause a level 5 earthquake, shaking the toiletries and banging against the sink vigorously. You would think they got married last week, but they’ve actually been together for fourteen years.

“They’re going for round 2,” jokes their friend Karen, watching the couple as they leave the party. Tom and Janet’s friends talk a lot of shit about their love life, which is fun at first, but then becomes mean and mean-spirited, and you start to wonder why any of these people hang out with them? Do they even like each other? Nope. But that’s the least of Tom and Janet’s worries.

After the tone shifts from sex farce to moody mystery, from soft focus romance to hard focus dutch angles, a man (Stephen Root) arrives at their door with a briefcase, explaining that he works for the city and they have a major malfunction–a rare dual malfunction– causing them to be horny 24/7 and to love one another unconditionally. It can all be solved with an injection, but Tom and Janet like the way they are, leading to a grisly murder and a trip to a spooky Airbnb with their so-called “friends”

The plot centers on the pair, as they try to figure out who sent the businessman (could it be prankster Karen?), along with a nightmare they have about couple’s therapy. They’re hoping to prove that their love is real and not some sort of cosmic mix-up. Along the way, love triangles form, emotional confessions are made and reckoned with, all while a haunted house plays tricks on them.

It’s not just the premise that makes this work, but also the execution of light comedy and heavy horror. The humor is humorous, the horror horrific. “Happily” draws from genre conventions but feels completely fresh. It’s a trip, and if you’re willing to follow that trip to the end of the road, it’s a trip worth taking. [B-]