WARNING: The following contains major spoilers for Pet Sematary, in theaters now.

As one of the bleakest, most horrific novels in Stephen King's entire bibliography, Pet Sematary doesn't pull punches as it weaves its haunting tale of loss. The novel and 1989 original film depict the Creed family losing their youngest child, toddler Gage, in a tragic accident on the road outside of their home. Mad with grief, Gage's father Louis exhumes his son's corpse and buries it in the cursed graveyard of the title, causing the toddler to rise from the dead, with sinister results. However, as revealed in trailers, the new adaptation makes a major change, with older sister Ellie instead killed by a speeding truck.

While Ellie does return to her parents as a twisted, evil version of her former self, the change is a major departure from the source material and earlier adaptation that reshapes the climax of the new film.

RELATED: Stephen King's Pet Sematary: Everything Goes Black in Chilling Final Trailer

Portrayed by Jeté Laurence, the resurrected Ellie uses her knowledge of her parents and family friend Jud to manipulate and cruelly taunt them before brutally attacking them. Changing which Creed child is killed and brought back from the grave helps to differentiate the 2019 adaptation from the original. However, the filmmakers also thought it would be more believable for the psychological horror to be committed by an 8-year old rather than by a toddler.

"There was something about an 8-year-old and the psychology that she would have," co-director Dennis Widmyer explained to Entertainment Weekly ahead of Pet Sematary's release. "She would understand what happened to her on the road. She would understand that she’s dead. She would know how to not only physically kill a person, but psychologically destroy them as well. It just gave another layer to it.”

RELATED: Pet Sematary: The Stephen King Adaptation Has Scary Good Early Reviews

In the film's climax, Ellie becomes a much more physical form of evil, knocking out her father and dragging him and her mother, whom she just murdered, to Pet Sematary so that the soil's malevolent spirits possess their bodies. With that level of exertion, even from a paranormal source, the filmmakers realized having the older child commit these sinister acts would be much more feasible, both believably and logistically with performances from child actors, at the hands of the older sibling.

Pet-Sematary-1

"Gage is so young, you can’t really do that much with him," admitted producer Lorenzo di Bonaventura. "So this way, we’re able to really get underneath our affected child. We’re able to get into the psychological horror of a child [coming back] because of her age.”

RELATED: Why the Pet Sematary Trailer Is So Effectively Unsettling

For Stephen King, the change is not only understandable, but also a departure the author himself felt was a good choice and nice twist for fans with preconceived expectations from the novel and original film.

Directed by Kevin Kölsch and Dennis Widmyer, Pet Sematary stars Jason Clarke, Amy Seimetz, Jeté Laurence, Hugo and Lucas Lavoie, and John Lithgow. The adaptation of the Stephen King novel opens Friday nationwide.