In the Mouth of Madness is a 1994 American supernatural horror film directed and scored by John Carpenter and written by Michael De Luca. It stars Sam Neill, Julie Carmen, Jürgen Prochnow, David Warner and Charlton Heston. Neill stars as John Trent, an insurance investigator who visits a small town while looking into the disappearance of a successful author of horror novels, and begins to question his sanity as the lines between reality and fiction seem to blur. Informally, the film is the third and final installment in what Carpenter refers to as his "Apocalypse Trilogy", preceded by The Thing (1982) and Prince of Darkness (1987).