Aylmer is a brilliant and recognized scientist and philosopher who has dropped his focus from his career and experiments to marry the beautiful Georgiana (who is physically perfect except for a small red birthmark in the shape of a hand on her cheek).
As the story progresses, Aylmer becomes unnaturally obsessed with the birthmark on Georgiana's cheek. One night, he dreams of cutting the birthmark out of his wife's cheek (removing it like scraping the skin from an apple) and then continuing all the way to her heart. He does not remember this dream until Georgiana asks about what his sleep-talking meant. When Aylmer remembers the details of his dream, Georgiana declares that she would risk her life having the birthmark removed from her cheek rather than to continue to endure Aylmer's horror and distress that comes upon him when he sees her.
The following day, Aylmer deliberates upon and then decides to take Georgiana to the apartments where he keeps a laboratory. He glances at Georgiana casually and normally but can't help but shudder violently at seeing her imperfection; Aylmer's reaction causes her to faint. When she awakens, he treats her warmly and comforts her with some of his scientific concoctions but when he attempts to take a portrait of her, the image is blurred save for her birthmark revealing the disgust he has of it.
He experiments some more and describes some of the successes to her but as he questions how she is feeling, Georgiana begins to suspect that Aylmer has been experimenting on her the entire time without her knowledge and consent. Aylmer catches her investigating, and accuses her of spying on him in the laboratory, and potentially damaging his valuable and delicate instruments. They argue briefly but not intensely. Georgiana then agrees to drink a potion Aylmer has concocted for her despite his warning that it might be dangerous to do so and may carry unexpected side effects.
Soon after, he brings her the potion and the potion is proven to be effective, in some respects, by rejuvenating a nearby plant with but a few drops. Upon seeing this and trusting her distressed husband, Georgiana drinks the concocted potion and promptly falls asleep. Aylmer watches the birthmark fade little by little. Once it is nearly gone, Georgiana wakes up and is pleased (like Aylmer) to see the results. However, the potion had side effects, and Georgiana soon tells her husband that she is slowly dying. Once the birthmark fades completely, Georgiana dies with it.