Huis clos is a legal term, the French equivalent of the American legal term in camera. It refers to a hearing or discussions with the judge in the privacy of his chambers (office rooms), or when spectators and jurors have been excluded from the courtroom. In English translation, Sartre’s play has been produced under the titles In Camera and No Exit.
A valet leads Joseph Garcin into a room, decorated in the style of the Second French Empire. Garcin is dead, and as the valet explains, this room is only one of the many rooms of hell. As Garcin explores, he is shocked to find no instruments of torture. There are also no mirrors. His toothbrush has been taken from him. The valet answers his questions, sometimes mockingly, and confirms that there is a buzzer for Garcin to press if help is needed, although it is frequently out of order and cannot be relied upon. Garcin is left on his own for a moment, then the valet arrives with the room’s second occupant, Inès Serrano. Inès takes Garcin to be the torturer, asking him the whereabouts of Florence, her lover who is also dead. When Garcin laughs and explains who he really is, Inès responds coldly. Garcin suggests that they try their best to maintain a polite cordiality, but Inès replies that she is “not polite” and refuses to cooperate. The valet finally arrives with the room’s third and final occupant, Estelle Rigault. Because Garcin’s face is hidden when she arrives, Estelle takes him for someone else and, in terror, begs him not to lift his head; she knows his face has been blown off. When she realizes her mistake, she at once concerns herself with the chairs in the room; she simply cannot sit in the green or burgundy chairs, because they would not match her dress. Garcin, at Inès’ prompting, offers her the blue chair. Introductions are made; the conversation begins.
At first, none of the three will admit the reason for their damnation. Garcin, who was editor of a non-violence magazine in Rio during his lifetime, says that he was executed for being a pacifist, while Estelle, a wealthy society wife who died of pneumonia, suggests that a mistake has been made in her case. Inès, a lesbian postal worker, demands that they all stop lying to themselves and confess to their moral crimes. She refuses to believe that they have all ended up in the room by accident and is the first to realize that they have been placed together to make each other miserable; she deduces that they are to be one another's torturers. Joseph states that, in that case, they must try to leave each other alone and each be completely silent. He hides his head and says he will spend his time “putting his life in order.” But Inès rebelliously begins to sing about an execution instead, while Estelle tries to catch Garcin’s attention by requesting a mirror to check her makeup. Inès tries to seduce Estelle by offering to be her "mirror" and describing everything she sees, but when Estelle continues seeking Garcin’s attention instead of responding to Inès’ romantic overtures, Inès starts mocking her instead. Their chatter finally becomes too much for Garcin, who angrily gives up his attempt to isolate himself in silence.
It becomes clear that Inès is attracted to Estelle, Estelle is attracted to Garcin, and Garcin is in no mood for romance at all.
Each of them has moments when s/he is able to see friends, family, and their old home amongst the living, as if a TV screen has been turned on that only the one concerned can see. The initial glimpses reveal that Garcin despises his wife, that Estelle’s friends and family aren’t as attached to her as she believed, that new renters are already moving into the apartment that Inès shared with her lover. Once Garcin, Estelle and Inès have been forgotten by the world of the living, their visions stop.
The three finally do confess to their crimes. Garcin admits that he mistreated his wife, cheating on her and taking pleasure in making her unhappy. Inès reveals that she seduced her cousin's wife, Florence, while living with them both and eventually drove Florence to suicide. At first Estelle continues to insist that she is innocent, but when Garcin and Inès begin guessing wrongly at what her sins may have been, Estelle becomes desperate and finally gives in. She confesses that she cheated on her husband, then murdered the resulting child, prompting the child's father to commit suicide.
These confessions only bring their relations with each other to new heights of verbal brutality. Garcin finally begins giving in to Estelle's attempts to seduce him, to Inès horror and anger. Garcin is tormented by self-doubt: is he a coward for attempting to flee his country during wartime? He hopes that if Estelle believes he is no coward, he will be able to set his own fears to rest. Estelle, wanting desperately to win Garcin, is ready to say nearly anything he wants to hear, but does not understand his obsession with cowardice and soon grows impatient with him. When Inès tells Garcin that Estelle is just feigning attraction to him so that she can be with a man, any man, Garcin abandons Estelle and attempts to escape the room. Ringing the buzzer has no effect; he pounds on the door over and over again. But when it inexplicably and suddenly opens, Garcin is unable to bring himself to leave. The others remain as well. Estelle tries to force Inès from the room, convinced that without Inès’ critical eye on them, she and Garcin would become lovers. But Garcin refuses to help get rid of Inès. He realizes that if he can convince Inès that he is no coward, he will be able to believe it himself. Inès encourages him to try and convince her, but finally judges him an absolute coward, and swears to make him miserable forever. Garcin cries out that rather than torture devices or physical punishment, "hell is other people." Estelle tried again to seduce him, but Garcin insists that he cannot make love to her while Inès is watching. Estelle, infuriated, picks up a paper knife and attacks Inès, stabbing her repeatedly. Inès only laughs, pointing out that, since they are all already dead, murder is impossible. As Estelle fully realizes that they are trapped in the room forever, they all begin to laugh hysterically, until Garcin says, "All right then, let’s keep going.”