True horror lies in an adult's understanding of grief
This is why I was surprised when I read that, in ranking all of King's novels, pop culture site The Vulture had placed Pet Sematary pretty high on the list: it clocks in at #18. More intriguing was the capsule review, which ended with "Parents, all too aware of the fragility of their young children, might find this book scariest of all."
What could I do? Realizing that I had only read the book once, probably 25 years ago, when I was a teenager, I had to re-read it.
Re-reading Pet Sematary as an adult was one of those rare experiences where it's like reading an entirely different book. Pet Sematary is about grief. Grief is the emotion that drives the entire narrative, the plot, the characters; it informs every aspect of every scene. Grief is even visible in the early parts of the book, before any of the present-tense characters die. There is death, and remembrance of death, and even when death isn't literally on the table, the knowledge of pending death lends every scene a poignant glow of instant nostalgia.
The book isn't different. The reader, however, is. The first time I read Pet Sematary I had only the barest experience with grief. I knew nothing of the way that grief can tear you open, destroy your ability to care, and turn your entire life to ashes.
There is a scene, late in the book, where Louis (the protagonist) sits at the edge of a grave, rocks the body of his dead son in his arms, and promises him that "it will be all right." That daddy will find a way to make it right, no matter what it takes. I won't lie: I got weepy. It's just… so… sad. It comes as a relief when the story turns to the cartoonishly bizarre horror set pieces, with the monsters and the magic and the stabbing.
The real horror lies in the scenes where a six-year-old girl silently carries around a photograph from the winter before, where she is pulling her younger brother on a sled, and they both are happy.