In 1969, The Highwayman, Dean Jagger, a seasoned member of an old World War II spy network, recruits Charles Rone, Patrick O'Neal, a young United States Navy intelligence officer, for a perilous mission. He assembles a tight, uneasy crew: Janis, Nigel Green, a drug dealer and pimp; The Warlock, George Sanders, a culturally sophisticated homosexual; and B.A., Barbara Parkins , a thief. Together they aim to retrieve a letter written without proper authorization that promises United States aid to the Soviet Union in destroying Chinese atomic weapons plants. The letter had been solicited on behalf of a high-level Soviet official by a man named Dmitri Polyakov, who had previously sold Soviet secrets to the U.S. that he had obtained from the official. When U.S. and British authorities learn of the letter, they arrange to buy it back from Polyakov, but he later commits suicide after being apprehended by Soviet counterintelligence, under the direction of Colonel Kosnov, Max von Sydow.
To secure the operation, the group blackmails Captain Potkin, the Soviet head of counterintelligence in the U.S., threatening his family in order to gain use of his vacant Moscow apartment. Once they reach the Soviet Union, the terminally ill Highwayman sacrifices his life to divert the attention of Soviet counterintelligence away from his teammates. To identify Polyakov’s contact, Janis teams up with a brothel operator who mentions a Chinese spy known as “The Kitai” as a possible source for names of officials and others to whom he can sell heroin, with which Janis already plans to keep the prostitutes addicted. Meanwhile, The Warlock infiltrates a circle of intellectual homosexuals and begins an affair with a university professor; one of the professor’s students was Polyakov’s former lover, who claims Polyakov had a relationship with Vladimir Bresnavitch of the Soviet Central Committee.
Years earlier, Bresnavitch had sought to oust Kosnov in favor of Robert Sturdevant, a primary operator from The Highwayman’s old group. Kosnov and Sturdevant had previously trusted each other to authorize agents across their territories, but Bresnavitch’s pressure pushes Kosnov to pull off something spectacular to save his position. He betrays Sturdevant’s trust, capturing his agents and earning Sturdevant’s enmity; Sturdevant eventually disappears, presumed to have killed himself. Bresnavitch had used Polyakov to fence stolen artworks in Paris, and Ward, an old partner of The Highwayman and a member of Rone’s current crew, travels there to pursue leads. On the morning of his return, Potkin reaches the Soviet Union and informs Bresnavitch about Rone’s operation.
As tension escalates, Janis, B.A., and Ward are captured, while The Warlock takes his own life before capture. Rone escapes and goes to the Kitai to arrange a re-purchase of the letter, only to be met with an attempt on his life by the Kitai, revealing that the Chinese possess the letter. Desperate, Rone turns to Erika Beck, the wife of Kosnov, with whom he has been involved, and discovers that Bresnavitch orchestrated the raid without the knowledge of Soviet counterintelligence, indicating Bresnavitch’s role as Polyakov’s traitorous contact. Rone vows to help Erika escape to the West, and she later informs him that B.A. has taken poison and is expected to die.
Rone’s leverage grows when he threatens to expose Bresnavitch unless Ward is released. Bresnavitch concedes, and Rone and Ward plan to depart the next day. But Ward, disapproving of Erika’s fate and Rone’s plan to aid her, kills Erika. He then confronts Kosnov, listing the names of agents betrayed by Kosnov, signaling retribution, and shoots Kosnov in the kneecap. Kosnov screams in pain as Ward closes in.
As they race toward a plane, Rone reveals a startling conclusion: Ward is actually Robert Sturdevant, intent on staying and having struck a deal with Bresnavitch to take over as the head of Soviet counterintelligence. Ward finally confirms that B.A. is alive and offers to secure her release in exchange for a favor, slipping Rone a dire note:
> Kill Potkin's wife and daughters or I kill the girl.
In the end, the web of loyalties, betrayals, and strategic moves leaves the players fractured, each maneuvering toward a fragile future in which trust is scarce and the cost of survival can be ruinously high.
