Jet is a 27-year-old law school dropout who recently moved back in with her wealthy parents in Woodstock, Vermont. Following a severe head injury from an unknown assailant, she refuses a highly risky surgery and is given fewer than seven days to live due to a pending aneurysm. Rather than resting, she uses her remaining time to investigate her own murder, displaying a reckless determination.

Billy is Jet's childhood best friend who works as a bartender and musician in Woodstock. He provides Jet with a place to stay when she leaves her parents' house and becomes her reluctant but loyal partner in investigating her attack. He serves as a moral anchor for Jet, grounding her when she makes reckless decisions.

Jack is a sergeant in the Woodstock Police Department and a long-time neighbor to the Mason family. He has served as a supportive figure in the community for years and frequently shares police updates with Jet despite protocols. He is fiercely protective of his son, Billy, and maintains close ties to the Mason family.

Luke is Jet's older brother who works tirelessly at his father's company, Mason Construction. He is driven by a desire to prove himself capable of taking over the family business. He frequently clashes with Jet, and his intense dedication to the company often makes him defensive and prone to angry outbursts.

Dianne is Jet's mother and a prominent town trustee in Woodstock. She is deeply distressed by Jet's decision to refuse brain surgery and aggressively pushes her to change her mind. She is fiercely protective of her family's image and wealth, though she harbors unresolved grief regarding past family tragedies.

Scott is Jet's father and the wealthy owner of Mason Construction. He suffers from polycystic kidney disease, a condition he passed on to Jet. While he tries to act as a peacemaker in the family, his primary focus remains his contracting business, which has earned him both wealth and the resentment of displaced locals.

Sophia is Luke's wife and the mother of their young son, Cameron. She was once one of Jet's closest friends, but the two have drifted apart over the years. She frequently visits the Mason family home and is deeply invested in ensuring her husband succeeds at taking over Mason Construction.

JJ is Jet's ex-boyfriend who envisioned a highly successful, traditional future for them, prompting Jet to end the relationship. After he disappears following the Halloween Fair and sends a suspicious text message, he becomes the police department's primary suspect in Jet's attack.

Andrew is a grieving local resident who harbors an intense, vocal hatred for the Mason family. He blames Dianne and Luke for destroying his family's life, citing Dianne's interference in his daughter's employment and Luke's demolition of his neighborhood for a construction project.

Dr. Lee is the neurosurgeon treating Jet at the hospital. She provides the concrete, fatal timeline regarding Jet's fractured clivus bone and forming aneurysm. She insists that Jet fully understand her options and supports her right to make her own medical decisions despite outside interference.

Detective Ecker is an investigator with the Vermont State Police assigned to Jet's case. He approaches the investigation methodically, focusing heavily on JJ Lim as the primary suspect, which frequently puts him at odds with Jet's own impatient and aggressive investigative tactics.

Chief Jankowski is the head of the Woodstock police force. He oversees the investigation into Jet's attack alongside the State Police and deals with the fallout from the Mason family's various conflicts in the town.

Henry is JJ's brother, an injured laborer struggling with severe medical debt after a workplace accident damaged his kneecap and eye. He is deeply afraid of the people he used to work for and lives in constant anxiety about his financial and physical wellbeing.

Emily is Jet's older sister who tragically drowned in the family pool seventeen years ago when Jet was a child. Her death is a defining trauma for the Mason family, causing Dianne to constantly compare Jet to her idealized memory of Emily.

Nina is Andrew's deceased daughter and Emily Mason's former best friend. She died by suicide shortly after being fired from her job. Her father blames her death entirely on Dianne Mason's influence in the town.

Owen is a local teenager who took official photographs at the Halloween Fair. He possesses hundreds of images from the night of the attack, making his computer a vital resource for tracking down who was wearing a specific costume.

Gerry is Owen's father and a town trustee who works alongside Dianne Mason. He is polite and cooperative, though he possesses knowledge about past threats made against Mason Construction during town meetings.

Nell is Chief Jankowski's wife and a wealthy business owner in her own right. She is currently in private negotiations to purchase Mason Construction, a fact that threatens Luke's presumed inheritance.

Reggie is Jet's loyal pet dog. He is highly sensitive to his surroundings, sensing the attacker in the house before the strike and later howling loudly enough to alert the neighbors to Jet's unconscious body.