Lucía and Edmundo Nóbile invite some people to dinner at their mansion. The servants leave without warning until only Julio, the butler, is left. After dinner, for some reason, the guests can’t bring themselves to leave: instead, they partly undress and sleep where they are.

​

In the morning, the guests realize they can’t leave the room. Over the next few days, they descend into anarchy: with the exception of the logical Dr. Carlos Conde, they become "thirsty, hungry, quarrelsome, hostile and hysterical." An elderly guest, Sergio Russell, dies, and his body is placed in a closet. A young engaged couple, Béatriz and Eduardo, lock themselves in another cupboard to commit suicide.

​

The guests break a wall to gain access to a water pipe; three sheep and a bear planned for after-dinner entertainment find their way into the room (the former are promptly slaughtered and devoured). Dr. Conde obtains a secret supply of morphine from Edmundo to administer to his patient, the cancer-ridden Leonora, but it is stolen by siblings Francisco and Juana. Ana, a Jew, tries to free the guests by performing an unsuccessful mystical ceremony.

​

As the guests reach breaking point, Raúl insists that Edmundo be sacrificed as punishment. At this point, Leticia notices that the remaining people are in the same positions they were in before their plight began. At her insistence, they reconstruct their gestures and conversations from the night of the party, and miraculously find themselves free to leave. They are greeted by the police and the servants, who were similarly unable to enter the premises.

​

The guests attend a Te Deum at a cathedral to give thanks for their salvation. When the service is over, the churchgoers and the clergy are similarly trapped in the church. The military begins firing at people in the street. The film ends with a flock of sheep entering the church in single file, to the sound of gunshots.