Tess DeNunzio, the 15-year-old narrator of Dear Zoe, writes letters to her younger sister Zoe, who died on September 11 while Tess was supposed to be watching her. Tess begins her story with a memory of her pregnant mother asking Tess and Tess’s younger sister, Em, to help choose a name for the baby because her mother “felt like she had this power with names she had to be careful with” (1). In Tess’s memory, they settle on Zoe because they don’t know anyone else with that name. Tess’s mother believes a unique name will make Zoe independent and confident, and Tess says it worked.

Tess’s mother had Tess when she was 19. She was married to Tess’s father while Tess was a baby, but when Tess was five, her mom married David, an attorney. They had Em, named after Emily Dickinson, when Tess was seven, and Zoe when Tess was nine. Though Zoe and Em are her half-sisters, Tess doesn’t think of them that way.

Tess feels like she has two fathers: David is the disciplinarian who loves to read and saves for Tess’s college education, and her biological father is “a mess,” but she loves him and briefly went to live with him after Zoe’s death.