In postwar Vienna, Austria, Holly Martins, a writer of pulp Westerns, arrives penniless as a guest of his childhood chum Harry Lime, only to learn he has died. Martins develops a conspiracy theory after learning of a "third man" present at the time of Harry's death, running into interference from British officer Major Calloway, and falling head-over-heels for Harry's grief-stricken lover, Anna.
After carrying out a flawlessly planned hit, Jef Costello, a contract killer with samurai instincts, finds himself caught between a persistent police investigator and a ruthless employer, and not even his armor of fedora and trench coat can protect him.
While recording sound effects for a slasher flick, Jack Terry stumbles upon a real-life horror: a car careening off a bridge and into a river. Jack jumps into the water and fishes out Sally from the car, but the other passenger is already dead — a governor intending to run for president. As Jack does some investigating of his tapes, and starts a perilous romance with Sally, he enters a tangled web of conspiracy that might leave him dead.
In 1984 East Berlin, dedicated Stasi officer Gerd Wiesler begins spying on a famous playwright and his actress-lover Christa-Maria. Wiesler becomes unexpectedly sympathetic to the couple, and faces conflicting loyalties when his superior takes a liking to Christa-Maria.
The story follows the manhunt for the Zodiac Killer, a serial killer who terrorized the San Francisco Bay Area during the late 1960s and early 1970s, taunting police with letters, bloodstained clothing, and ciphers mailed to newspapers.