As both the protagonist and the narrator of Delirium, Lena explains that in the United States, love has been categorized as a disease (namely, “amor deliria nervosa”) by the Consortium (a group of government scientists) for the past 64 years. For the past 43 years, everyone has undergone a cure for this disease upon reaching their 18th birthday. The disease is described at length in The Safety, Health, and Happiness Handbook, colloquially known as The Book of Shhh. Lena’s older sister, Rachel, has been cured for nine years, while Lena is scheduled to be cured in 95 days. At the opening of the story, she is looking forward to the procedure because she has witnessed the ways in which love brings only pain and death to those who experience it. She recalls a girl throwing herself off a building, choosing death over being cured.

Lena lives in Portland, Maine, with her aunt, uncle, and younger cousins Grace and Jenny, the daughters of Lena’s late cousin Marcia. Marcia died after her husband, a scientist accused of being a love sympathizer, disappeared. Marcia was indicted in his place and suffered a heart attack soon after.