Harry Caul, a skilled electronic surveillance expert, is tasked with recording a private conversation between a young couple in Union Square. He's a devout Catholic and jazz lover who is intensely private and solitary, which creates tension with his business associate Stan. As Harry listens to the recording, he believes the couple's lives are in danger and must decide whether to turn the recording over to his client, the director, or try to save the couple's lives using information from the recording.

The Conversation
A surveillance expert's world is turned upside down when he uncovers evidence that the couple he's been watching may be in grave danger, leading to a crisis of conscience that threatens to redefine his very identity.