Dr. Louis Creed relocates with his wife Rachel, their two young children, Ellie and Gage, and their cat Church from Boston to rural Maine, seeking a quieter, safer life. Their new home is an idyllic retreat, but it borders a mysterious stretch of woods that includes a peculiar pet cemetery (spelled "sematary" by the local children) where the town's children have buried their deceased animals for generations. Unknown to the Creeds, the cemetery is steeped in sinister myth and dark legend, involving rituals that date back many years.

Their neighbor, Jud Crandall, befriends the family and soon shares with them the eerie lore surrounding the local land. He reveals the existence of another burial grounds beyond the pet cemetery, believed by locals to have the power to resurrect the dead. After tragedy strikes and Church is killed by a truck, a heartbroken Ellie prompts Louis to consider an unthinkable action. Driven by grief and desperate for a solution, Louis contemplates crossing a line from which there might be no return, setting off a chain of events with unfathomable consequences that threaten to unravel the Creed family’s lives.