A pair of hands meticulously crops images from a fashion magazine for a personal scrapbook. The hands belong to an unassuming and conservative physician named Julián. He runs a radiology clinic from his personal residence, assisted by a shy, mild-mannered nurse named Ana.
One afternoon, Julián is invited to the house of the mother of his friend Pablo, a charismatic and sophisticated adventurer who has recently returned from Africa with the unexpected news that he has married a beautiful and carefree young woman named Elena. Pablo hands Julián a drink, his favorite peppermint frappe, as the group awaits the entrance of Elena, who is upstairs dressing. The sight of the captivating Elena visibly stuns Julián, as Elena reminds him of a mysterious woman he had seen beating drums during the famous Holy Week ritual in the village of Calanda. She insists that she has never seen him before, nor has she ever been to Calanda. Despite her rebukes, Julián finds himself immediately drawn to Elena's cosmopolitan demeanor.
During the days that follow their first encounter, Julián becomes increasingly infatuated with Elena and finds pretext to spend time with her. While Pablo is busy, Julián takes Elena sightseeing to Cuenca. Despite her indifference to his attentions, Julián's obsession with Elena does not diminish. Frustrated by his inability to win Elena's affection, Julián turns his attention to his laboratory assistant, Ana, who has secretly pined for Julián. A sexual liaison between the two is soon established. Julián manipulates Ana, coercing her to dress and groom herself like Elena does.
While involved with Ana, Julián continues to pursue Elena, but she resists his advances with open derision. Julián invites Pablo and Elena to his cottage on the countryside to spend the weekend. He takes them on a tour of the grounds of the abandoned spa where he and Pablo used to play as children.
After a practical joke by Pablo and Elena, aimed at humiliating Julián (Elena showing up with a drum), Julián begins to plan an elaborate revenge against the couple. Picking up Elena's curiosity about his relationship with Ana, Julián invites Elena and Pablo to join him and Ana in his country house.
Before Pablo and Elena arrive, Julián has Ana drugged and, while she is sleeping, places what appears to be the same drug in a decanter containing peppermint frappe. When Pablo and Elena arrive, Julián tells them that Ana will be a little late and offers them the beverage. After a few sips, the couple begins to ridicule Julián once again. When they succumb to the drug, Julián carries their bodies to their car which he causes to roll off a cliff, giving the appearance that the couple had died in an automobile accident. Returning to his country house, Julián finds the place cleared of all incriminating traces and Ana being dressed as the woman of Calanda. The film ends as the two embrace.
