Sophie (Elisabeth Moss) and Ethan (Mark Duplass) go on a couples retreat in an attempt to save their marriage in “The One I Love.” (RADIUS-TWC)

The marriage therapist who sends troubled husband and wife Ethan and Sophie to a couple’s retreat in “The One I Love” isn’t lying when he says it’ll be just the two of them.

At the same time, he ain’t exactly telling the truth either.

Ted Danson, who plays the therapist, is the only actor on-screen with lines besides Mark Duplass and Elisabeth Moss, who portray Ethan and Sophie. After an affair by Ethan, they’re trying to “reset the reset button,” as their counselor puts it, by spending a long weekend in an idyllic guest house in Southern California’s Ojai Valley. What (or who) they find when they get there is the subject of this twisty, original and provocative film, which is sort of a romantic comedy, sort of a relationship drama and sort of a sci-fi thriller. It’s clever — at times almost too clever for its own good — but also a refreshingly grown-up departure from the mindless fare of summer.

Things get weird for Ethan and Sophie pretty quickly, in ways that have nothing to do with the joint they smoke upon arriving at the secluded enclave. Without spoiling things, it’s safe to say that each of them is forced to confront each other and themselves in ways for which they — and probably you — are wholly unprepared.

That confrontation, which builds to a slightly wobbly but satisfying conclusion, is kind of funny, but only rarely ha-ha. The humor of Justin Lader’s script, which almost anyone in a committed relationship will recognize, is tempered by a tone of light but mounting creepiness, courtesy of director Charlie McDowell’s unwillingness to dumb down the dread-laced subject matter. He wants you to laugh, yes, but also to think. Maybe even to be a little disturbed.

That combination leads down some interesting byways.

See, Ethan and Sophie’s therapist has played a kind of trick on them, which they catch onto only slowly. Even after they do, the fact that they continue to play along with what turns out to be the most extreme version of a role-playing game imaginable — a weird, alternate-dimension version of “Who’s Afraid of Virginia Woolf?,” as Ethan cracks — doesn’t seem forced or phony.

That’s because the film’s biggest trick is the one it plays on the audience. “The One I Love” manages to work both as a metaphor and as a slightly surreal form of kitchen-sink drama. Duplass and Moss are so good, and their reactions to the frankly nutty circumstances of the film are so plausible, that the preposterous premise of the story hits home both conceptually and emotionally.

It’s a tough thing to pull off, especially in a movie that is essentially an intellectual exercise. Like figures in a funhouse that is both philosophical and phantasmagoric, the characters in “The One I Love” spook you, both inside your head and inside your heart.

★ ★ ★

R. At area theaters. Contains obscenity, drug use and sex. 91 minutes.