This short story by Carlos Fuentes centers on Felipe Montero, a young historian and teacher, and Consuelo Llorente, an enigmatic widow.

We learn that Felipe first meets Consuelo after he answers an ad asking for the services of a historian. When Felipe heads to 815 Donceles Street (the address given), he is surprised to find that Consuelo's husband, General Llorente, died sixty years ago and it is his memoirs he must prepare for publishing.

Felipe is even more surprised to find that Consuelo lives with Aura, her beautiful young niece, who appears to be a mysterious blend of an apparition and human being.

As he spends more time at Consuelo's home, Felipe finds himself progressively drawn to Aura. He can't take his eyes off her and even more strangely, begins to feel emotions he has always known to exist but had never before experienced.

As for Consuelo, the old lady appears to be obsessed with strange religious rituals centered around Christ, Mary the Virgin, St. Sebastian, the archangel Michael, and demons.

In due time, Consuelo gives Felipe General Llorente's memoirs. They tell of the former soldier's war exploits and subsequent exile to France. He works on editing the papers and decides that, for four thousand pesos, he's willing to put up with the old lady's idiosyncrasies.

At mealtimes, he notices that Consuelo and Aura's movements mirror that of each other. Privately, Felipe begins to lust after Aura; he develops an unexplained yearning to free her from what he thinks is Consuelo's wicked hold upon her defenseless young niece.

One night, he wakes up after a terrible dream and imagines that Aura is kissing his whole body. They make love, and the surreal experience appears to be strangely real. After their lovemaking, Aura proclaims that Felipe is her husband. He agrees unequivocally.

As time progresses, Felipe concludes that Consuelo must be at at least 109 years old, based on calculations he made from the general's memoirs.

As Felipe proceeds with his work, however, he finds strange happenings occurring. One day, Felipe discovers Aura beheading and skinning a goat. When he enters the old lady's chambers, he finds Consuelo mirroring Aura's movements in killing and skinning the animal.

Later, he discovers that Aura has aged. Previously, she had appeared to be a girl of twenty. At present, she looks as if she has aged twenty years. One day, after another surreal lovemaking experience, Aura demands that Felipe promise to love her forever. For his part, Felipe agrees to do so.

Later, Felipe pores through more of General Llorente's memoirs. In them, he discovers Consuelo's obsession with obscure rituals that promise to preserve her youth and beauty. He also discovers (disturbingly) photos of what looks like Aura and the general. As he continues to stare at the photos, he realizes with horror that his features have now been transposed onto the general's face.

The story ends with Felipe making love to Aura, only to discover that she has transformed into Consuelo and he, into Colonel Llorente. Consuelo admits to Felipe that she has only ever been able to keep Aura around for three days at a time. She promises unequivocally that she will bring Aura back once more.