Horror icon Sam Raimi takes his shot at a “Castaway” tale in the “Admirable Crichton,” “Swept Away” vein with “Send Help,” an over-the-top romp in the Raimi “Drag Me to Hell” style.

It’s about class and sexism, survivalism and revenge showcased in extreme close-ups that punch jokes right in the nose, violence that will pin your ears back and a dressed-down Rachel McAdams flipping the script on the movie that made her — “Mean Girls.”

And even though it gives away one twist/gag too easily and tends to pummel us in the finale, I have no notes. This is a damned funny riff on “Survivor” and the very idea that the dainty McAdams might have a little “Misery” era Kath Bates in her.

McAdams plays the uncool “victim” here — dowdy, 40ish Linda Liddel, the “workhorse” at Preston Strategic Solutions. But being a little older than the rest of the staff, she doesn’t fit in socially. She dresses down, right down to her “practical” comfortable shoes. She feels the need to suggest “googling” her “go to” song in bar-karaoke. “One Way or Another” by Blondie might as well be “Bringing in the Sheaves” to the bros and Gen Zs that fill out the staff there, the ones who don’t INVITE her to karaoke night.

Not that these Tau Kappa Dipsticks give two damns what the bespectabled numbers “savant” who does all the digital heavy lifting there thinks or says.

Linda’s on-the-spectrum awkward. So that vice presidency promotion that the now-late-founder of the firm promised her before his death is out the door when his frat-bro-promoting son (Dylan O’Brien) takes over.

The guy’s rich, young and entitled, with just enough biz school “management” track study under his belt to suffer Linda’s attention if only to “handle” her. The sharp-dressed slacker (Xavier Samuel) frat brother who steals credit for Linda’s work gets to promotion.

But they need her along when they close a big deal in Thailand. A lot of extra work is her consolation prize. She’s been humiliated to her face by this sexist creep, showing off for his model-fiance (Edyll Ismail). One last insult? The bros all watch a pirated copy of Linda’s goofy audition tape for “Survivor” on the private jet they’re all taking to Bangkok.

Payback is a bitch, and it starts the second the jet loses power and starts to go down. In short order, Linda the “Survivor” fanatic and her injured, no real skills in life Gen Z boss are stranded on an island in the Gulf of Thailand.

She proceeds to “Survivor” the s–t out of this dilemma, relishing every survival skill she learned for a show she never got on but gets to try out now. And everything she can do that he can’t is just more leverage in this class/status reversal.

The script by Damien Shannon and Mark Swift does a blunt-instrument chiseling in of Linda’s character — over-sharing to colleagues who could not care less, confessing her dreams to her pet cockatiel, lacking the spine, the wardrobe or the makeover to “make it” in the culture where she works, and not having a clue about that.

Raimi plays with the camera — exTREME closeups of senior partner Dennis Haysbert’s nose as he sniffs an errant dab of tuna salad from Linda’s uncleaned lip, funny/scary jolts of Linda having nightmares over how far she can take this status-reversal thing she’s playing with her hapless “boss,” a stunning drone shot -pull back from Linda on the beach, tipping its hat to “Castaway” and then throwing the latest tech in Robert Zemeckis’ and Tom Hanks’ faces.

But it is McAdams and O’Brien (“Maze Runner,” “Saturday Night” and TV’s “Teen Wolf” alumus) who make the sale here. They give their characters edges and strained efforts to hide those edges, if only for a little while. The way O’Brien’s Bradley oversells “Love the backpack. You make that TODAY?” to Linda’s latest latticework palm fronds creation, how McAdams hits just the right newly-hinted-at menace when she intones “We’re not in the office any more, Bradley,” grounds the characters in an amusing reality.

The film’s gender politics and Gen Z slaps aren’t going to earn universe endorsements. But Raimi’s delivered a laugh-out-loud variation on a well-worn theme. And those of us lucky enough to remember his body of work and age with him (look for the vintage Delta 88 wagon, kids, and Sam’s daughter in the office scenes) can appreciate the novel horrific touches he can bring even to the pedestrian of genre films even if some people are more the butt of the joke that in on it.

Rating: R, gory violence, profanity

Cast: Rachel McAdams, Dylan O’Brien, Edyll Ismail, Xavier Samuel and Dennis Haysbert.

Credits: Directed by Sam Raimi, scripted by Damien Shannon and Mark Swift. A 20th Century Studios release.

Running time: 1:53