Sophie, the granddaughter of Princeton's revered thinker Dr. Niemarck, begins a correspondence with Muriel, the family maid, many years after her grandfather's death. She asks if Muriel knows what happened at a long ago Christmas party that forever changed her parents' relationship with her grandparents.

In between describing memories of her employment to the family, Muriel mentions that Dr. Niemarck became an alcoholic in his later years, and had left her money in his will before his death. Mrs. Niemarck had refused the money. Now an old, lonely woman, Muriel asks Sophie if she could make reparations in the form of $15,700.

Sophie confesses she cannot afford to send Muriel the money in full, but begins sending installments. Musing about the past, Sophie accidentally mentions Walter Kaufman, a Princeton scholar who was like a second son to Dr. Niemarck.

An upset Muriel reveals that Walter was her first love, but that Dr. Niemark and his wife disapproved of the match because of her lower-class status. Muriel's hatred for the Niemarcks starts to rise to the surface, and she finally reveals the events of that Christmas party.

She'd found a pornographic magazine in Dr. Niemarck's office one day and had placed a page in between little Sophie's book for her parents to find at the Christmas party. Disgusted, the family turned on Dr. Niemarck, who in shame, resorted to alcoholism.

Muriel reminisces with sadistic glee how he became depressed and increasingly dependent on her afterwards until his death. In her final letter, Muriel thanks Sophie for reminding her of her victory over the Niemarcks.