“Thanksgiving,” Eli Roth’s latest slasher film, begins with a convincing, tense Black Friday sequence.  Outside a Plymouth big box store, an unruly crowd grows restive.

The security is minimal and obnoxious teens who are friends of the owners gain early access and pointedly flaunt their VIP status inside the glass-walled building.  Suddenly, all restraint snaps and the crowd storms the store. No one is thinking of the French storming the Bastille but the result is similar:  Dead bodies, injured patrons followed by a pathetic blame game.

With this the most riveting sequence in the seasonally appropriate “Thanksgiving,” the saga jumps a year as another Black Friday looms and Plymouth citizens start dying — being exterminated in the most cruel and despicable ways imaginable.

There’s a back story here – “Thanksgiving” has its origins in a mock trailer Roth made for the 2007 horror hit “Grindhouse” which had Quentin Tarantino’s instant classic about a killer stuntman “Death Proof” on a double bill with Robert Rodriguez’ zombie flick “Planet Terror.”  Roth provided one of three Coming Attractions and that has now been made vividly real.

On the case is Plymouth police sheriff Newlon (Patrick Dempsey, currently and rather incongruously People magazine’s Sexiest Man Alive).  This is one sheriff who you eventually realize is remarkably lousy at his job.

After all, as an ax-wielding psycho in a mask stalks Plymouth with shall we say pointed references to its very first Thanksgiving, the body count continues to mount, all executed in increasingly disturbing ways.

Decapitation? That’s almost expected.  But basting and roasting a woman in a large industrial oven?

The many mutilations, beginning with that Black Friday riot and continuing until the final credits, rate as both spectacularly and ingeniously depraved and very twisted, earning cheers as well as disgust.

Roth, a Newton South high school graduate who has consistently pushed boundaries in a career that began over 20 years ago, has announced that there will be no Unrated version arriving anywhere like a DVD Extra, that his “hard R” rating has let him go as far as he cares to do so.

The “Thanksgiving” cast includes “Showgirls” survivor Gina Gershon, TikTok star Addison Rae, who is very effective as our besieged heroine, Milo Manheim, Karen Cliche and Jalen Thomas Brooks.

“Thanksgiving”

Rated R. At the AMC Boston Common, South Bay Center, Causeway and suburban theaters. Grade: B