Tom Welles (Nicolas Cage) is a surveillance expert on the rise. He's living the American dream with a wife, Amy (Catherine Keener), infant daughter, and a house in the suburbs of Harrisburg, Pennsylvania. After the completion of an assignment for a U.S. Senator, Welles is summoned to the house of a recently deceased captain of industry. His widow, in settling his estate, has discovered an 8MM film in her late husband's private safe. The silent short depicts the apparent murder of a young woman by a large, masked figure, what is known as a "snuff" film. Greatly disturbed by the film's contents, the widow hires Welles to find the identity of the woman and determine if she is still alive. Welles finds the girl's identity and follows her trail from the time she ran away from home to Hollywood. Once there, Welles meets adult bookstore clerk Max California (Joaquin Phoenix) to act as Virgil to Welles' Dante. As the two begin their descent into the world of underground pornography, the detective grows more and more distant from his family, as if he cannot shake the taint of the world in which he now walks. Tom and Max eventually meet pornographers Dino Velvet (Peter Stormare) and Eddie Poole (James Gandolfini). By this time the detective finds he can no longer walk out of the inferno.

After meeting a general, war correspondent Dick Ennis (Robert Mitchum) is assigned to accompany US Army Rangers for the upcoming attempt to outflank the tough enemy defenses. The amphibious landing is unopposed, but the bumbling American general is too cautious, preferring to fortify his beachhead before advancing inland. Ennis and a Ranger drive in a jeep through the countryside, discovering there are few Germans between the beachhead and Rome, but his information is ignored. As a result, the German commander, Kesselring, has time to gather his forces and launch an effective counterattack. Ennis is with the Rangers when they are ambushed at the Battle of Cisterna. From there, the film departs from being a view of all sides and levels of the campaign to a story of a handful of survivors making their way back through enemy lines. Ennis asks what makes one human being willingly kill another. Corporal Jack Rabinoff (Peter Falk) replies that he loves it, and his lifestyle makes him live more than anyone else. Rabinoff is based on a real 1st Special Service Force soldier Jake Wallenstein, who ran an illegal brothel of Italian prostitutes in a stolen ambulance.[2] Most of the men, including Rabinoff, are killed (in reality, Wallenstein was killed by shrapnel at Port Cros during Operation Dragoon, the invasion of southern France.[3]) Ennis survives to publicly question the competence of the Allied commander.