Overview
"The Oath" is the twelfth episode of the first season of the period drama television series The Americans. It originally aired on FX in the United States on April 24, 2013.
Plot
Sanford Prince (Tim Hopper) tells KGB agent Elizabeth Jennings (Keri Russell) that he has recruited an Air Force colonel named Lyle Rennhull who will give the Soviets important information on the SDI project for $50,000. Elizabeth brings this new information to her husband Philip (Matthew Rhys), who is wary, citing Prince's gambling addiction. Elizabeth believes Sanford is delivering them the "highest source" within the Reagan administration, while Philip believes it could be a trap.
Elizabeth receives material from Prince at a dead drop, containing schematics for the U.S. missile defense system. She meets Claudia (Margo Martindale) who believes that the Americans wouldn't hand over such important information just as a trap, telling Elizabeth that she believes the Colonel is real and a meeting with him has been set. Elizabeth has grown tired of Claudia as their handler and tells Philip that she wants her to be reassigned. Philip resolves to convince FBI employee Martha (Alison Wright) to plant a bug in Gaad's office to see if the FBI are planning anything. Later, while at dinner, Philip (disguised as FBI counterintelligence agent Clark) proposes to Martha, who happily accepts.
Nina's (Annet Mahendru) suspicions about Stan Beeman (Noah Emmerich) grow and she accuses him of murdering Vlad, which he strongly denies. Philip asks Martha to plant a listening device in Gaad's office and she agrees. Viola Johnson (Tonye Patano), who planted the bugged clock in Weinberger's study, has been feeling increasingly guilty, and eventually confesses to the FBI. She tells Stan and Gaad what happened, and they surmise that Viola was threatened by the same couple who kidnapped Patterson. Viola agrees to speak to a sketch artist. The FBI discover the bug in Weinberger's study and decide to leave it there now that they know the Russians are listening.
From Wikipedia (CC BY-SA 4.0).