The novel opens in medias res, with the unnamed narrator reflecting on her and her son Root’s relationship with the Professor. The Professor nicknamed her son “Root” because of the flat top of his head, which reminded him of a square root sign. Of the “countless” things the Professor taught them, the meaning of square root was the most important. The Professor never cared if they got something wrong, “for he believed that mistakes were often as revealing as the right answers” (2). Moreover, he “had enormous respect for matters about which he had no knowledge” and didn’t mind taking the back seat when appropriate (3).

The narrator comes to work for the Professor in March 1992 when her employer, the Akebono Housekeeping Agency, assigns her to his home. She knows that the assignment will be difficult because he has already gone through nine housekeepers; however, she is known for working dutifully for difficult clients.

She is interviewed by the Professor’s widowed sister-in-law, who explains that the tasks are relatively simple: The narrator must come in on weekdays, fix lunch and dinner, clean the house, and do the shopping. When the narrator asks to meet the Professor, his sister-in-law says no: The Professor would not remember her, as his memory lasts only 80 minutes at a time as the result of a car accident in 1975.