Two rivaling reporters working for the Washington Post, Bob Woodward (Robert Redford) and Carl Bernstein (Dustin Hoffman), research the botched 1972 burglary of the Democratic Party Headquarters at the Watergate apartment complex. With assistance from a mysterious source, "Deep Throat" (Hal Holbrook), the two reporters make a connection between the burglars and a White House staff member.
Holly Martins, an American author of western fiction, arrives in post–war Vienna looking for his childhood friend, Harry Lime (Orson Welles), only to learn that Lime has died. Viewing his death as suspicious, Martins elects to stay in Vienna and investigate the matter. Martins develops a conspiracy theory after learning of a "third man" present at the time of Harry's death.
After the death of her famous opera-singing aunt, Paula (Ingrid Bergman) is sent to study in Italy to become an opera singer as well. While there, she falls in love with the charming Gregory Anton (Charles Boyer). The two return to London and Paula begins to notice strange things happening such as missing pictures, strange footsteps at night, and gaslights that dim without being touched. As she fights to retain her sanity, her new husband's intentions come into question.
