Travolta plays Jack, a sound technician for a low-budget exploitation film, who is told to find more a realistic scream for a slasher victim. One night, he's out in the woods by a road, recording general sound effects. A car comes down the road, there's an explosion, and it goes off the side of the road and into the water. Jack rushes to the water and jumps in. He discovers a man dead in the car and a woman named Sally (Allen) trying to get out. Eventually, Jack is able to break a window in the car and pull Sally out to safety.
At the hospital, Jack discovers the man in the car was Governor McRyan, a possible presidential candidate. Lawrence Henry, McRyan's chief adviser, tells Jack not to tell anyone else about Sally being in the car. Jack is okay with that, at first. He's less okay with the fact Henry and the police seem content with the explanation McRyan's tire simply blew out. Jack is sure he recorded the tire being shot out right before the car went over the water. What he doesn't know is the man who shot out the tire, Burke (Lithgow), who was working on behalf of others to stop McRyan, is now out to get both Jack and Sally.
Quentin Tarantino, no less, has called this De Palma's best film and one of his three favourite films.
This film features the tropes:
- Be All My Sins Remembered: The final scene makes it pretty clear that Jack added Sally's dying scream to the slasher film in order to self-flagellate himself for the act of not saving her.
- Blackmail: It's why Sally was in the car and Manny was taking photographs; to blackmail McRyan into dropping out of the race. Of course, Burke had other plans...
- Book-Ends: The film begins and ends in the editing room of the exploitation film Jack was working on.
- Brick Joke: A pretty dark one. At the beginning of the film, Jack is trying to record a good scream for the film-within-a-film. He ends up using Sally's dying scream.
- Conspiracy Theorist: Everyone (except Donahue, the TV reporter) dismisses Jack as this; even Sally, when she of all people has reason to believe him.
- Cut Phone Lines: Burke disconnects Jack's phone so Frank Donahue can't call him back, allowing Burke to take his place in a meeting with Sally.
- Disposable Sex Worker: Among the women who resemble Sally that Burke kills to make his eventual attempt on her life less suspicious is a prostitute in a subway station.
- Does This Remind You of Anything?: The plot takes elements of several real-life political scandals, including Chappaquiddick, JFK's assassination (specifically the conspiracy theories revolving around a police bike's dictabelt recording of the assassination) and Watergate.
- Downer Ending: Jack manages to kill the assassin, but Sally is also killed. Ironically, as a result, the cover-up is a success. Making it worse is that Sally's dying screams are perfect for the terrible slasher movie Jack is working on. The final shot is of Jack cringing in the studio as the screams haunt him over and over.
- Exact Words: Burke's Establishing Character Moment is him contacting the people who hired him after he's killed McRyan. They are foaming at the mouth for such an action and he tells them back that he was hired to "take (McRyan) out of the race", and killing him was "within the parameters of the order".
- Even Evil Has Standards: The conspiracy that hired Burke wants absolutely nothing more to do with him after he kills McRyan, partially because his job is done, partially because they got sick with his psychotic tactics and they only wanted to Blackmail McRyan. Even then, Burke decides to clean up loose ends...
- Grievous Bottley Harm: Sally smashes a beer bottle over a drunken Manny Karp's head when he tries to forcefully kiss her, knocking him out cold.
- Hell Is That Noise: Sally's dying scream, for Jack.
- Heroic BSoD: Jack is going to be haunted by Sally's screams forever. And no one else will know...
- Hidden Wire: Jack placed this on an undercover cop, which ultimately failed when the cop's frequent sweating shorted out the battery. This led to his cover being blown, followed by his death.
- Karma Houdini: The people who hired Burke are never captured or even suspected. On their (feeble) defense, they invoke Even Evil Has Standards on Burke and cut him loose early in the film.
- My Greatest Failure: Jack tells Sally why the cops don't trust him: Jack once helped set up an undercover cop for a wire, but the cop's constant sweating shorted out the battery and exposed him, which led to the cop's execution and his teammates blaming Jack for the screw-up. By the end of the movie Jack has an even nastier failure haunting him for the rest of his life...
- The Oner: There are a few of these, including the entire Slasher Movie sequence, and a continuous, panoramic view of Jack's studio as he discovers that his tapes have been erased.
- Proscenium Reveal: The film begins with a first-person view of a Serial Killer prowling a co-ed dorm filled with all sorts of sleaze. Then he opens the shower curtain on a victim who lets out a completely unconvincing scream. Cut to Jack and his B-Movie producer laughing at, and then arguing over the scream in the Slasher Movie whose rough cut they have just been watching.
- Psycho for Hire: Burke. He quite enjoys the murders he commits.
- Rewind, Replay, Repeat: Jack does this in his studio so he can sync the audio he recorded of the crash with Karp's photos of the same.
- Serial Killer: Played with; Burke pretends to be one so his eventual murder of Sally won't be as suspicious, but he is heavily implied to be a sociopath anyway.
- Serial Killings, Specific Target: As mentioned above, Burke plots to kill Sally, the last witness, but doesn't want to make her murder look suspicious. He begins targeting women who look like her in the hope that, when he finally does get around to killing Sally, she'll be dismissed as just another victim of the lone psycho. That's exactly how it ends up playing out.
- Show Within a Show: Co-Ed Frenzy, the sleazy Slasher Movie Jack is working on, which we see an excerpt of in the beginning.
- Spiritual Successor: To Blow Up and The Conversation. The ending in particular is one to Chinatown.
- Spotting the Thread: Jack can't shake the feeling he heard something wrong about the supposed tire blow out he witnessed. He keeps playing the sound recording over and over until he realizes the "pop" happens before the car swerved, and he recognizes that "pop" as a rifle shot...
- Take That!: The horror film Jack is working on, and which we see at the beginning, is De Palma's slam at slasher films; ironic, since critics lumped his previous film, Dressed To Kill, in with other slasher films.
- Trapped in a Sinking Car: Sally is this after the crash, and Jack dives in to save her.
- Troubled Backstory Flashback: Jack used to work for the police department, until he wired an undercover cop whose cover was blown - the cop was sweating so much it shorted the wire, and he was found out - and the cop was killed as a result. We see the story play out as he tells it to Sally.
- Also counts as Foreshadowing; he wires Sally for her meeting with whom she thinks is Donahue, and although things don't go exactly the same, they end up just as badly.