Stephen King’s latest novel, 11/22/63, is a bit slow getting started but then it soars in a gripping and sometimes terrifying “what if” flight of fancy: what if you could change history, what if you could go back in time and prevent a hunting accident, a hot-blooded murder, or the assassination of John F. Kennedy? Would you, if you could? Be careful what you wish for.

Narrator and manly hero Jake Epping goes back to the late nineteen fifties and stays on, at the behest of another, to prevent Lee Harvey Oswald from taking those fateful shots from the sixth floor of the Texas School Book Depository. Along the way he meets up with a host of characters from the post-World War II, pre-Vietnam age, an age like any other with its racism, sexism, conformity, and fear of annihilation. But it was also an age before fast food and fake food, urban sprawl and Florida real estate, and cell phones and the internet — and for Epping, those differences tether him to the past as much as the wife-beating, White-only signs, and repressed sexuality repel him. Epping falls in love, thereby complicating his fight against evil — and make no mistake, this book is about good versus evil, angels versus devils, and the dark side attacking the light. Decency and goodness can prevail but not vanquish — and it is up to Epping to make sure the final equation isn’t the other way round, with evil ruling and goodness holed up in crummy little dens of withering faith.

King is a master story-teller and if the characters in this book don’t run quite as deep as some of his others from past novels, they do enchant, where appropriate, and disgust, as needed. Certainly his Lee Harvey Oswald is multi-layered, a pathetic, nasty, stupid but crafty man who took an opportunity and changed history — but as King elucidates in this mind-boggling foray into time travel, history changes every moment, depending on how we react to it.

The climax of the novel — the “what if” answered — is brutal, melodramatic, soul-sucking, and horrifying. It is also absolutely necessary, for it illustrates King’s point that the most we can hope for from history is to learn from history. If only we can learn from it. The novel does, in the end, offer the hope that the best in humanity can flourish and overcome the worst, and on this day commemorating Martin Luther King, I cling to that hope — I, too, have a dream. But last night 11/22/63 gave me nightmares.