Probably the most accurate Stephen King adaption yet. Not surprising, since King himself wrote the screenplay. The story follows the Creed family moving into a beautiful Maine house. One of the other residents is Jud, a pleasant old man who knows a few things about the area. One is the highway that runs right through their frontyard. The other is a path leading to the Pet Sematary, where children for decades have buried the animals killed by the highway. Soon enough, Ellie Creed's cat, Church, is found dead. Luckily, this happens while the family, with the exception of Louis(the father), is away for Thanksgiving. Jud takes Louis to another burial ground, beyond the Pet Sematary, where Church is to be buried. Later, Louis is greeted(not so politely) by Church. He's returned, appearing to have chewed his way out of the bag he had been buried in. Maybe he was buried alive. Maybe not. Nothing more I can say without ruining the story.
Of all the King adaptions I've seen this would be the most terrifying. The characters are real and the situations are normal. Mary Lambert does a great job directing the proceedings. Suspense is kept fairly high throughout the film, due in part to the plot development. The scene where Gage is killed will stick in your mind forever. Then, of course, we have the conclusion. Easy to determine what's going to happen, but Lambert pulls off some genuinely scary, and sometimes disturbing, moments.
Overall, this is a good film and an excellent adaption. If you enjoy being scared and don't mind being haunted by some occasionally disturbing images then "Pet Sematary" is just what you're looking for. Non Horror fans will want to avoid this.