A New York commercial artist and his wife and daughter move to a quiet, rustic New England village they visited during their travels, only to find themselves mixed up in ritualistic lifestyle full of foreboding secrets.

Surveillance expert Harry Caul is hired by a mysterious client's brusque aide to tail a young couple. Tracking the pair through San Francisco's Union Square, Caul and his associate Stan manage to record a cryptic conversation between them. Tormented by memories of a previous case that ended badly, Caul becomes obsessed with the resulting tape, trying to determine if the couple is in danger.