Content Warning: The source text references multiple deaths by suicide and deals with the psychological effects of trauma, loss, and grief. It also uses stigmatizing and potentially offensive language to refer to people experiencing mental illness.

Lock Every Door’s New York City setting structures its examinations of urban isolation and social status. Jules Larsen’s life is already defined by loneliness and alienation when she accepts her job apartment-sitting at the renowned Bartholomew building on Manhattan’s Upper West Side. The neighborhood is teeming with wealthy, elite inhabitants, making Jules immediately feel like she doesn’t belong. The impostor syndrome her job at the Bartholomew inspires in her compounds her isolation, and the conflicts she faces result from these socioeconomic dynamics. The novel’s interest in loneliness and isolation is part of a larger movement in fiction in the wake of the 2020 COVID-19 pandemic. Though Lock Every Door doesn’t take its temporal cues from the 2020 lockdown, Jules considers her time at the Bartholomew as similar to “solitary confinement.”

Jules struggles to make ends meet in New York ahead of her job at the Bartholomew. After losing her job, she fears that her limited qualifications will keep her from new steady employment.