Sixteen-year-old Jessie Holmes, the story's narrator, explains how much her life has recently changed as result of her mother dying of cancer about two years ago: her father Bill eloped with a woman named Rachel he met in an online bereavement group and decided to move with Jessie from Chicago to California to live with Rachel and her son, Theo.

A week into her junior year at her new, elite private school (Wood Valley High), Jessie receives an anonymous email from a 16-year-old boy calling himself “Somebody Nobody.” He offers to be her “virtual spirit guide,” in an attempt to help her navigate and adjust to the “war zone” of her new school. Assuming it is a prank, Jessie declines his offer. He insists that he is genuine, and they banter back and forth, ending the conversation with some suggestive, flirtatious jokes. Jessie recognizes that the confidence with which she speaks online does not match her personality; the extra time allows her to be the “better, edited version of [herself]” (7). She doubts the intentions of “SN” and admits to herself that she is weak and feels “lost and confused and alone as [she has] ever been” (8).