Lena is a 17-year-old girl who recently escaped Portland for the unregulated territory known as the Wilds. She operates under the alias Lena Morgan Jones while attending Quincy Edwards High School for Girls in Brooklyn. She uses a fabricated cure scar to pass as a compliant citizen while secretly working for the resistance. Her intense grief over the apparent death of her lover drives her to build physical and emotional endurance in harsh conditions.

Julian is the 18-year-old son of a prominent pro-cure activist. He remains uncured due to a recurring brain tumor that makes the mandated surgery too dangerous. He serves as a public figure for the Deliria-Free America organization and frequently gives speeches supporting the government's ideology. Despite his public conformity, he secretly explores forbidden books and images of natural landscapes.

Raven is a young woman who leads an underground homestead in the Wilds near Rochester, New Hampshire. She enforces strict rules within her community and demands that residents focus entirely on present survival rather than past trauma. She directs the group's seasonal relocation and manages their limited resources. Her harsh exterior hides a deep sense of responsibility for the vulnerable people in her care.

Thomas Fineman is the founder of Deliria-Free America. He actively campaigns to enforce the mandatory emotional cure across the population. He treats romantic attachment as a dangerous disease and uses political rallies to gather support for strict government policies. He maintains a tightly controlled public image while keeping forbidden materials locked in his private study.

Tack is a skilled scout and hunter who lives in the unregulated Wilds. He procures food for the homestead and maps out routes for their winter relocation. He maintains a gruff attitude and openly doubts the abilities of newcomers. He prefers direct communication over hidden agendas and hoards banned books in a secret basement location.

Alex is an uncured resistance operative from Portland. He accompanied Lena during her initial flight toward the border fence. He sacrificed his own freedom to ensure she could cross into the unregulated territory. Lena uses the memory of his dedication to motivate her physical training.

Sarah is a 12-year-old girl who lives in the underground ruins of a destroyed town. She acts as a guide for newcomers and explains the community's scavenging methods. She deeply admires the older resistance members and eagerly adopts their slang and philosophies.

Blue is a young child living in the unregulated territory. She relies entirely on the protection of the older homesteaders. She experiences frequent illness and nighttime terrors as the harsh winter weather approaches.

Hunter is a friendly resident of the underground homestead in the Wilds. He understands the secret communication systems used by sympathizers across the border. He takes time to explain survival mechanisms to new arrivals.

Coin is a leader among the outcast community living in the abandoned subway tunnels beneath New York City. She has a severe facial difference that makes her a target in the heavily regulated surface society. She provides medical care to those who fall into the tunnels.

Rat-Man is a guide who lives in the decommissioned subway stations beneath Manhattan. He refused the mandated cure to preserve the memory of a woman he loved. He commands the rats that inhabit the tunnels and moves easily through the subterranean darkness.

Matt is a guard working with a violent faction of scavengers. He wears heavy boots and sports a tattoo of an eagle and a syringe on his body. He monitors captives held in an underground facility.

Annabel is Lena's mother who opposed the mandatory cure. She was imprisoned in the underground Crypts of Portland for over a decade before escaping into the Wilds. Her history of defiance heavily influences Lena's understanding of the government.

Miyako is a scout for the resistance group living in the New Hampshire Wilds. She undertakes physically demanding tasks in freezing weather to ensure the community has adequate supplies.

Hana is Lena's former best friend who lives in Portland. She recently received the surgical cure that removes the ability to feel intense emotion. She represents the compliant, regulated life Lena permanently abandoned.