“BRIGSBY BEAR”

***

(PG-13, 1:37)

The absurd and absurdly charming “Brigsby Bear” sounds, well, unbearable. It’s the story of a young man who, after decades of being shut away from the world, splashes down in it like a space alien. There are reasons for his re-entry, though that’s getting ahead of the story, which uses a queasy crime as a jumping-off point to spin a largely sweet, often very funny fairy tale about the perils and the sustaining pleasures of obsessive fandom.

Mostly, it is an account of one man’s great, mad love, one that’s mocked, tested and deemed near-pathological — a familiar plight for many superfans.

The obsession in question is “Brigsby Bear,” an amusingly weird live-action children’s television show that James (Kyle Mooney) has been faithfully watching since childhood. Now somewhere in his 20s, James shows no sign of moving on.

He doesn’t merely love the plucky, heroic bear — as well as Brigsby’s adorable helpers, the Smiles Sisters, and his villainous foe, the Sun Snatcher; James has absorbed the show, its stories and ethos into his being. His walls are lined with images from it; his shelves are crammed with recordings of each episode and related paraphernalia. He can mouth old dialogue verbatim. He even sleeps on “Brigsby” sheets, as if tucking into his own fanboy nest.

If this sounds familiar, it’s no wonder. Who, after all, hasn’t taped a Marilyn Monroe poster on her college-dorm door or hung a really nice poster for the film “Anatomy of a Murder” on a wall? People have been surrounding themselves with objects of worship since time immemorial, even if today’s fetish is more likely to be a Chewbacca collectible than a terra-cotta object.

Sure, in the age of global corporate media and cross-platform branding, fandom is a cradle-to-grave commodity lifestyle, from “Star Wars” onesies to superhero coffins. And, yes, this isn’t always cosplay; it’s a matter of life (and death).

That’s partly what “Brigsby Bear” is about, though mostly it’s a sweet and sometimes delightful melancholic story of a lonely man saved by imagination and love. That sounds like a bushel of cornball and might have devolved into pure ick if the director, Dave McCary, didn’t lead from the heart and wasn’t adept at navigating seemingly clashing tones. He hooks you early with an uneasily ha-ha, strange opener in which James and two others — Jane Adams plays April while a warm, wonderful Mark Hamill plays Ted — engage in “Brigsby” banter. Soon sirens are flashing and the movie darkens; a few beats later it brightens, then swerves into silliness only to veer into seriousness.

Much of what follows involves James’ confusing, awkward reintroduction into the world, or what some call adulthood. There’s the family he’s never met (Matt Walsh, Michaela Watkins, Ryan Simpkins), a friendly cop (Greg Kinnear) and a clueless therapist (Claire Danes). There are new buddies (Jorge Lendeborg Jr.), who with smiles, mood enhancers and some unpersuasive narrative nudging help usher James into the here and now.

Yet James, having been cut off from Brigsby World, can’t quit the bear, who’s seen every so often saving the day in some of the wittily conceptualized, visually degraded television clips sprinkled throughout the movie. And, really, why should James turn off the love?

Mooney, currently cutting it up on “Saturday Night Live,” manages the twists and tonal fluctuations in “Brigsby Bear” beautifully. (He wrote the story and shares screenwriting credit with Kevin Costello.) It’s no surprise that he can sustain and complicate a deadpan. But what makes the character work is the unconditional emotional seriousness that shapes the performance, deepening each glance and gesture. McCary fills the movie with modest comic jolts, from James’ shock of hair to the near-Lynchian cardboard surrealism of the “Brigsby” show.

The biggest jolt, though, is how each laugh brings forth more feeling in a movie that flirts with tragedy but opts for joy.