The series is set during the Cold War and follows Elizabeth and Philip Jennings, two Soviet KGB intelligence officers posing as an American married couple living in Falls Church, a Virginia suburb of Washington, D.C., with their American-born children Paige and Henry.
At the Rezidentura, Oleg (Costa Ronin) tells Arkady (Lev Gorn) that while he declined Tatiana's offer, he will go back to Russia with his mother.
He declares him persona non grata for his recent actions and orders him to leave the United States within 48 hours, with Tatiana (Vera Cherny) taking over his position.
William is placed on the United States Army Medical Research Institute of Infectious Diseases for treatment, and he refuses to disclose information to Stan and Aderholt (Brandon J. Dirden), as he will die in a few days.
Gabriel (Frank Langella) worries that William could speak with the FBI, and tells Philip and Elizabeth (Keri Russell) that they should consider leaving the country.
The site's consensus states: "'Persona Non Grata' serves up new developments, additional tragedies, and unsettling reveals in a shocking season finale of The Americans.
Club gave the episode an "A–" grade and wrote, "Taking place during one of the Cold War's hottest years, season four brings The Americans to a boiling point.
Certain landmark events affect the characters' day-to-day, but so do David Copperfield specials, crummy computer games, and the death of someone thousands of miles away.
"[11] Mike Hale of The New York Times wrote, "The final scene captured the grim paradox of William's description: the Jenningses dream home looming over Philip and Paige in the dark, a repository of secrets, lies and deadly peril.
"[12] Genevieve Koski of Vulture gave the episode a 4 star rating out of 5 and wrote, "Family can be a great source of comfort, but it can also be a huge liability.
[...] Though this point has been implicit from the start of the series, 'Persona Non Grata' drives it home, in characteristically tense fashion, as it closes an excellent, particularly domestic season of The Americans.
"[14] Matt Brennan of Slant Magazine wrote, "'We're all Americans now,' Young Hee declared in 'Experimental Prototype City of Tomorrow,' and 'Persona Non Grata' returns to this notion by transforming it into the ultimate dilemma, built into the composition of a single, telling image.
"[15] Alec Bojalad of Den of Geek gave the episode a 4 star rating out of 5 and wrote, "The lack of resolution should be frustrating and it should be the mark of a bad finale.
"[17] For the episode, Joel Fields and Joe Weisberg were nominated for Outstanding Writing for a Drama Series at the 68th Primetime Emmy Awards.