In 1994, John Carpenter was several years removed from his last bona fide triumph—1988's They Live—but he still hadn’t given up. (He’d sorta do that the next year, with Village of the Damned). His mindfuck extravaganza In the Mouth of Madness borrows heavily from H.P. Lovecraft and Stephen King, but it’s also its own bizarre creation.
Almost the entire movie takes place in flashback—a tactic that Carpenter would overuse in Ghosts of Mars, his last major release. Screenwriter Michael De Luca (Freddy’s Dead: The Final Nightmare) uses it here as a framing device; in the opening scene, we observe a straightjacketed John Trent (Sam Neill) being tossed into a padded room. He doesn’t believe he should be there—but isn’t part of being insane not knowing that you’re insane? At any rate, he’s eager to share his wild tale with the curious Dr. Wrenn (David Warner), who listens as the story plays out onscreen.
A talented insurance investigator—illustrated by a scene in which he charmingly disarms a fraudster, played by Carpenter regular Peter Jason—Trent is retained by a publishing house (headed by boss-man Charlton Heston) that’s desperate to locate horror author Sutter Cane. The missing Cane is the company’s most valuable asset, and he’s overdue with his next book. His legions of obsessed fans are getting restless, to the point of mob violence. And speaking of violence, Cane’s agent... well, he’s the guy with the axe.
Despite that unpleasant encounter, and the fact that he apparently loathes reading, Trent takes the job—confident he’s about to expose yet another case of fraud. He heads to the mysterious and maybe nonexistent town of Hobb’s End, New Hampshire to track down the elusive author, with a reluctant traveling companion: Cane’s longtime editor, Linda Styles (Julie Carmen), who sparks with Trent, even though she treats him with cool disdain.
Even before they hit the road, there are hints that all is not well in the universe, even if the ever-smirking Trent doesn’t notice at first. (His reaction to the axe attack is amazingly nonchalant.) Of course, since all of the events are unfolding via Trent’s storytelling, there’s no guarantee that his recollections are accurate—and as the movie progresses, reality becomes ever more fluid and freaky. Even straight-arrow Linda starts hallucinating... or does she? The scenes in which she appears without Trent present have to be Trent’s own imagining of what occurred, if the movie’s flashback structure is to make any sense.
Of course, making sense isn’t exactly what In the Mouth of Madness is aiming for.
“What scares me about Cane’s work is what might happen if reality shared his point of view,” Linda explains to Trent. “Reality is just what we tell each other it is. Sane and insane could easily switch places if the insane were to become a majority. You would find yourself locked in a padded cell, wondering what happened to the world.”
Trent, of course, brushes her off, but since we know that’s where he ends up, all that’s left to do is wait for sane and insane to swap out. And there’s no better location for that than Hobb’s End, which adds Twilight Zone to that Lovecraft/King cocktail we’re already wallowing in, is quaint and eerie and—Linda points out with growing terror—ripped straight from Cane’s as-yet-unreleased latest work, which is not coincidentally titled In the Mouth of Madness.
But Trent, still believing it’s all a publicity stunt to promote Cane’s next bestseller, stubbornly refuses to acknowledge that any of the funny business going on around him is really happening. He’s blind, unlike all of the characters he keeps encountering who announce, with no small amount of menace, “I see!” or “He sees you!”
By the time Trent and Cane (Jurgen Prochnow) meet, Trent is still not ready to believe Cane’s assertion that his books have bled into reality because so many people read them, and have come to believe in them. Like the Bible. “There has to be some kind of explanation for what I’ve seen tonight,” the logic-minded insurance man mutters. Cane counters by telling him to read his new book: “It will drive you absolutely mad!” You don’t say!
Trent clings to his version of reality as long as possible, because the flip side—that reality has come to share Cane’s point of view, as Linda predicted, with the added twist that Trent is merely one of Cane’s characters—is too insane to fathom.
The whole point to this hall of mirrors is that Cane’s new book is merely a conduit for the slithery Old Ones, who will be able to return and take over once all of humanity goes insane, which will happen once everyone reads In the Mouth of Madness (or sees the movie, because of course there’s a movie!) and mutates into a beast. Or something.
After a certain point you’d be forgiven for deciding not to try and hold the plot to anything resembling coherence. A far more rewarding way to watch In the Mouth of Madness is to simply view it as an ambitious but flawed meta-narrative about insanity—and soak up all that gleeful, slime-and-tentacle creature horror while you’re at it.