In the Mouth of Madness (also known as John Carpenter's In the Mouth of Madness) is a 1995 horror film directed by John Carpenter and written by Michael de Luca, who was at the time in charge of New Line Cinema.
After reading some of Sutter Cane's novels, John begins to have vivid nightmares, and also encounters several readers of Cane's, who act listless and trance-like. Styles remarks that Cane's work has been known to affect "less stable readers," and has caused disorientation, memory loss, and severe paranoia. Upon inspecting the covers of his books, John notices a series of intricate red lines, which assembled, form the shape of New Hampshire, and identify one town, which is alluded to be Hobb's End, the fictional setting for many of Cane's works (This is also an allusion to Stephen King, who sets many of his works in Castle Rock). John believes the town to be real, just old and remote enough to not be listed on a current map.
Styles and John depart, searching for Hobb's End. Along the way, Styles passes a young boy riding a bicycle, who she passes a second time, though his visage significantly changes. Upon seeing the bicycle rider a third time, she strikes him with the car. He gets up and walks away, astounding John and Linda. The next length of the journey takes place, and Linda notices the yellow road lines vanish. After rolling down the window and looking outside, she appears to be driving over thunderhead storm clouds. She begins to panic when she finally finds herself driving through a rustic covered bridge, and comes out right next to a sign for Hobb's End. John, asleep for this entire time, compliments Styles for finding it.
Linda and John check into a hotel, also famous in Cane's stories, and meet Mrs. Pickman, a famous Cane character. Mr. Pickman is later shown shackled to his wife's ankle, starving to death and in obvious pain. The main article of interest is The Black Church, described in many Cane books as the fount of evil that's polluting the entire town. John and Linda approach the church when a group of townspeople attack, wielding shotguns and torches, demanding Cane to return. The children of the town have mysteriously vanished, and Johnny, one of the children, appears in the Church, supplanted by Cane himself. After being briefly revealed, the townspeople are set upon by attack dogs and driven off.
John, enraged by what he believes to be a choreographed event, is preparing to leave when Linda suggests that the events described in Canes work's are really happening, and John laughs this idea off as insane. Linda steals John's car keys, preventing him from leaving. Linda enters the church to confront Cane, and is exposed to Cane's ultimate work, the titular "In the Mouth of Madness."
Back in town, John is in a nearby bar drinking, when one of the townspeople from the church approaches, and begins to question his existence, thinking himself to be a character in a book. John compliments the man's acting ability and the level of skill displayed by their group theatrics, but the man persists. John, driven beyond all tolerance, screams that this is reality and not a Sutter Cane story. The man comments that reality is not what it used to be, and commits suicide with a shotgun, saying "I have to, he wrote me this way," when John attempts to stop him.
Fleeing the bar, John sees a group of townspeople, obviously mutated and monstrous in appearance, approach him with shotguns and torches. John returns to the hotel, and discovers Mrs. Pickman and Linda have been similarly altered. John attempts to flee using the car, but is repeatedly teleported back to the center of town in front of the mutant mob. He eventually crashes after attempting to run the crowd down and swerving to avoid hitting Linda. He awakens in a Catholic confessional, and Sutter Cane, sitting on the other side of the divide, begins to talk about his eventual plan, to free a race of ancient beings to reclaim the Earth for themselves, with him as a new deity. This forces John to experience intense hallucinations and visions, before bringing him to his studio, where he has just completed the book. He informs John that he is nothing more than a character in one of his stories, and he has no choice but to return the manuscript and begin the destruction of humanity.
After giving John the manuscript, Sutter Cane tears open his face like a piece of paper, ripping a hole that leads into darkness. John flees, appearing near the highway, dirty and torn, clutching a copy of the manuscript. As he returns to New York City, he repeatedly receives and burns new copies of the manuscript. Finally arriving at Arkham, he finds that he apparently delivered the manuscript months ago, and that the book has been on sale for weeks, and that a movie is shortly being released.
John has a total mental breakdown, and murders several people with a fire axe, which leads to him being arrested. The agent dismisses him as insane, and leaves. Later that night, John is again visited by Cane, who reveals that this is not John's ending. John wakes the following day to find his cell door torn from its hinges and the residents of the asylum slaughtered. He departs, hearing over an ambulance radio that the rest of the world is suddenly overrun with mutant creatures and outbreaks of suicide and psychotic mass murders. After seeing himself on a movie billboard, John enters a theater running the movie adaptation of In the Mouth of Madness. John laughs hysterically as he watches the meta-film (identical to the real film) showing him everything he has just experienced, and as it "catches up" to his current situation his laughter becomes insanity-laced sobs of despair.
Arkham Publishing is named after a town frequently referred to in the works of H.P. Lovecraft, and Lovecraft correspondent August Derleth actually founded a publishing company called "Arkham House" in the 1940s, which reprinted material from the influential pulp magazine, Weird Tales.
The name "Sutter Cane" is a tribute to the horror author Stephen King, many of whose novels are set in small New England towns.
All of Sutter Cane's novels have similar titles to H.P. Lovecraft's books.