Grace is a 17-year-old high school student living in Mercy Falls, Minnesota. Since surviving a wolf attack as a child, she has felt an unexplained affinity for the wolves in the woods behind her house, particularly one with golden eyes. She feels emotionally distant from her distracted parents and relies on herself. She prefers reading history and nonfiction over poetry, maintaining a practical and grounded outlook on life.

Sam is an 18-year-old werewolf with striking yellow-gold eyes who shifts between human and wolf forms based on the temperature. He loves poetry, playing the guitar, and the warmth of the summer when he can remain human. He carries deep psychological and physical scars from an abusive childhood and dreads the approach of winter, which triggers his lupine transformation.

Beck is a former lawyer who acts as the leader of the Mercy Falls werewolf pack when they are in human form. He maintains a large safe house stocked with supplies for the wolves. He is a paternal figure who desires a family, leading him to rescue a young Sam and raise him.

Isabel is a wealthy, conventionally attractive high school student with blonde curls and a white SUV. She presents an arrogant, superficial exterior to her classmates. However, she is highly observant and fiercely dedicated to her family, refusing to accept the town's easy explanations regarding her brother Jack.

Jack is a high school student from the wealthy Culpeper family. He has curly dark hair and a reputation around school as a bully with a short temper. His sudden disappearance at the edge of the woods sparks a frantic and dangerous wolf hunt organized by the townspeople.

Olivia is Grace's painfully shy best friend. She has tanned skin, dark hair, and bright green eyes. An avid photographer, she spends hours near the Boundary Wood documenting the local wolf pack. She is a straight-A student who relies on facts and initially dismisses Grace's supernatural theories.

Shelby is a young woman who carries physical scars from a lifetime of human abuse and a wolf attack. She has a southern accent and blonde hair in her human form, and a white coat with icy blue eyes as a wolf. She prefers her animal form and radiates hostility toward outsiders, viewing the human world with deep mistrust.

Lewis is Grace's father. He works an office job and provides well for his family financially, but remains emotionally distant. He is deeply focused on his wife and his career, frequently forgetting his parental responsibilities to the point of endangering Grace when she was younger.

Amy is Grace's mother, a self-absorbed artist who spends most of her time painting in her studio. She expresses disappointment that her daughter prefers practical subjects and numbers over art, leading her to keep a detached distance from Grace's daily life.

Rachel is a friendly, outgoing high school student who acts as the social glue between Grace and Olivia. She frequently plans trips and social outings, keeping the trio connected despite their diverging interests.

Paul is one of the older members of the Mercy Falls pack. He serves as the primary leader of the group when they are in their wolf forms, working in tandem with Beck's leadership in the human world.

Ulrik is an older werewolf of German heritage within the Mercy Falls pack. He acts as an eccentric uncle figure to Sam, occasionally swearing and holding cynical views about the benefits of human education for wolves.

Officer Koening is a local policeman in Mercy Falls. He attempts to manage the town's rising panic following Jack's disappearance, advocating for standard police procedures over vigilante wolf hunts.

John is Olivia's handsome older brother. He provides transportation for his sister and takes opportunities to casually flirt with her friends.

Tom is the wealthy patriarch of the Culpeper family. He is known throughout Mercy Falls as an unpleasant man and an avid hunter who proudly displays animal trophies in his large home.

Chloe is a small Chihuahua belonging to Isabel Culpeper. Isabel frequently dresses the dog in outfits that match her own handbags.