It seems that M. Night Shyamalan has the end of days on his mind. A couple of years ago, he pondered the quandary of aging in “Old.” In his latest film, he turns toward the apocalypse, or at least the idea of it, in “Knock at the Cabin,” adapted from Paul Tremblay’s 2018 horror novel “The Cabin at the End of the World.”

Tremblay’s novel is terrifying in its unpredictability and ambiguity. Structured around a home invasion that takes place over the course of a couple of days, it explores the ways in which a stunning amount of suffering can occur if someone believes enough in their mission, misguided or not. “Knock at the Cabin,” adapted by Shyamalan, Steve Desmond and Michael Sherman, is faithful to the source material until it is not, because this wouldn’t be a Shyamalan movie without his own original take on the ending.

Shyamalan films are always perfectly cast. There are no better actors to play the main trio than Ben Aldridge, Jonathan Groff and Dave Bautista, who tear into these challenging roles with an emotional and technical rigor. The rest of the small cast is uniformly excellent, including the incredible Kristen Cui in her first film role.

Cui plays Wen, the young adopted daughter of Andrew (Aldridge) and Eric (Groff). She’s catching grasshoppers outside their remote lakeside vacation rental when a strange person approaches. Leonard (Bautista) seems to be a gentle giant, but soon he’s intoning scary promises about hard choices that will shortly need to be made. Wen scurries inside and her dads lock the doors, but the quartet of Leonard, Redmond (Rupert Grint), Sabrina (Nikki Amuka-Bird) and Ardiane (Abby Quinn), make their way in nevertheless, in order to present the family with a choice: sacrifice one of their own or watch the apocalypse unfold.

It’s a straightforward if extreme concept, and the majority of the film takes place inside the walls of this vacation rental.

There are detours into Eric and Andrew’s flashbacks, and TV news reports that seemingly underline Leonard’s warnings, but the power of this story is that it takes place entirely among this group of seven.

Whether or not the apocalypse is actually happening is not the interesting part of this story of humanity, love and destruction. In his book, Tremblay hit on something that would become worryingly relevant in the past few years — the phenomena of collective mass delusions that can cohere online, usually revolving around doomsday scenarios. It’s the delusions that are horrifying here, not the doomsday. Tremblay knows that, but it seems that Shyamalan and his co-writers don’t subscribe to that notion, and their tweaks to this story, despite the impeccable cinematic craft and tremendous acting on display, hobble the adaptation’s power.

Movie details: Rated R for violence and language; funning time, 100 minutes. Grade: B