In Brian De Palma’s masterful psychological thriller, a movie sound technician (John Travolta) accidentally records evidence of a political assassination while capturing ambient sounds for a film. As he digs deeper, paranoia, obsession, and corruption spiral into tragedy. Stylish, paranoid, and deeply cinematic, Blow Out stands among De Palma’s most acclaimed works.

Criterion Collection

In the enthralling Blow Out, brilliantly crafted by Brian De Palma, John Travolta gives one of his greatest performances, as a film sound-effects man who believes he has accidentally recorded a political assassination. To uncover the truth, he enlists the help of a possible eyewitness to the crime (Nancy Allen), who may be in danger herself. With its jolting stylistic flourishes, intricate plot, profoundly felt characterizations, and gritty evocation of early-1980s Philadelphia, Blow Out is an American paranoia thriller unlike any other, as well as a devilish reflection on moviemaking.

Från IMDB:
A movie sound recordist accidentally records the evidence that proves that a car accident was actually murder and consequently finds himself in danger.