"The Conversation" presents a gripping thriller examining how fear and suspicion can infiltrate every part of someone’s existence after an unsettling revelation. Hired to record a conversation between two individuals in public, Harry Caul (Gene Hackman) provides his client with a clear recording. He carries the burden of regret from a past assignment that resulted in harm to those involved, including the deaths of a woman and child, which causes him to doubt his work. Although colleagues, friends, and even suppliers of surveillance technology regard Harry as exceptionally skilled, he’s visibly lost confidence and direction. This decline is demonstrated through several incidents: his apartment can be easily entered and searched, his mail is read, and he's tricked at a trade show by a rival who plants listening devices on him. His girlfriend observes that he was seen "hiding and watching for a whole hour" near the staircase. Despite having an unlisted number, both his landlord and client manage to contact him unexpectedly. After repeated listens to the recordings, Harry comes to think that the people in the conversation are worried about potential danger or even death related to their actions. His girlfriend/escort points out that a job is still a job, regardless of feelings, but weighed down by guilt, he doesn’t complete his task. He again demonstrates poor judgment when he allows the tapes to be taken (by his girlfriend/escort). The film ends with the realization that conversations can be misunderstood and aren't always straightforward, further intensifying Harry’s paranoia. Discovering the truth about "The Conversation" ultimately leads to a very satisfying resolution.

Source on TMDB