Ethan is a 45-year-old physician who formerly spent ten years as a special agent with the Wisconsin Division of Criminal Investigation. He specialized in crimes against children but retired when the emotional trauma became too overwhelming. He remains heavily fixated on the man who murdered his father, attending every parole hearing to ensure the killer remains behind bars. Ethan is highly competent and possesses a strong internal drive to protect and help others.

Francis is a convicted murderer currently serving a sixty-year sentence in solitary confinement at a maximum-security prison in Boscobel, Wisconsin. He was convicted decades ago for the murder of Ethan's father and remains the prime suspect in a series of historical local murders. He maintains a disturbing level of influence over others, utilizing manipulation and intimidation to control situations from within his cell.

Maddie is a police officer in Milwaukee who survived a horrific abduction when she was seventeen years old. She carries physical and emotional scars from the ordeal, including a permanent mark on her chest left by her captor. She bonds with Ethan over their shared history and provides crucial emotional and investigative support as they look into a cold case.

Lindsay is a successful psychologist who founded The Anonymous Client, a company offering fully encrypted virtual therapy sessions. She grew up in Cherryview as a star volleyball player alongside her best friend, who disappeared ten years ago. Lindsay cites the tragic loss of her childhood friend as the primary motivation for dedicating her life to mental health and helping others process their emotions.

Callie is a seventeen-year-old high school volleyball star whose sudden disappearance ten years ago remains an unsolved cold case. During the summer she vanished from Lake Okoboji, she was navigating significant life changes, including her parents' divorce, academic pressures, and an unexpected pregnancy. The recent reopening of her investigation serves as the catalyst for Ethan's return to police work.

Harriett Alshon/Eugenia is a woman who maintains a deep, obsessive correspondence with an incarcerated murderer. She keeps a shrine dedicated to his life and past crimes hidden in her home. Her intense fascination with the inmate drives her to follow his instructions from outside the prison walls, acting as his proxy in the real world.

Pete is an investigator with the Wisconsin Division of Criminal Investigation and Ethan's former partner. After being diagnosed with terminal ALS, Pete approaches Ethan with a personal request to reopen and solve the cold case of Callie Jones before he dies. He is determined to find answers for the community and the grieving family.

Christian is a retired tech mogul who recently sold his Silicon Valley company for billions and moved to a massive house on Lake Okoboji. He meets Ethan as an emergency room patient and quickly strikes up a rapport. He utilizes his advanced technological skills to assist Ethan in recovering deleted text messages and tracking digital footprints.

Blake is a former high school volleyball coach who currently works as a head groundskeeper for a wealthy family's estate near Beaver Dam. He coached Callie during the summer she disappeared and becomes a subject of Ethan's investigation when old text messages link them together.

Mark is the recently elected governor of Wisconsin and the father of Callie Jones. Despite his deep personal connection to the tragedy, he uses his political authority to officially reopen his daughter's cold case. He appoints Ethan to lead the investigation, recognizing his flawless past record.

Henry is Ethan's late father, who was killed when Ethan was thirteen years old. His death left a lasting emotional void in Ethan's life and initially drove his son into criminal investigative work. His past interactions with a notorious criminal remain a pivotal point of Ethan's trauma.

Kai is a member of the Ojibwe tribe and a loyal friend to Ethan at Lake Morikawa. He helps watch over Ethan's isolated family cabin and frequently goes fishing with him. He provides Ethan with a sense of community, safety, and escape from his stressful job.

Portia is a research assistant from the University of Wisconsin-Milwaukee who was recently reported missing. Her sudden disappearance becomes unexpectedly entangled with the cold case Ethan is actively investigating.

Andre is a guard at the maximum-security prison in Boscobel, Wisconsin. He oversees the solitary confinement unit and regularly interacts with high-profile inmates, trading privileges and information in ways that compromise prison security.

Damien is Callie's stepfather. He is highly critical of Callie, viewing her as selfish and detrimental to the family's public image during his political campaigns. His presence in the home is a major source of tension for the family.

Jaycee is Callie's younger sister and a fellow volleyball player. She shares a minor sibling rivalry with Callie regarding her athletic abilities but proves loyal by helping keep her sister's movements secret during the summer she disappears.

Cheryl is a supervisor at a Planned Parenthood clinic in Chicago. She provides Ethan with crucial context about a memorable visit a young woman made to the clinic shortly before she vanished, offering insight into the missing girl's state of mind.

Nicholas is Portia Vail's former fiancé. After the two experienced a brief reconciliation, Portia ceased contact with him, prompting an anxious Nicholas to file a formal missing persons report with the police.

Ari is the warden of the Wisconsin Secure Program Facility. He manages the maximum-security prison and finds himself pressured by political figures to approve highly unusual housing transfers for notorious inmates.

Hugh is a resident of Lake Morikawa who owns one of the few isolated cabins near Ethan's family property. His remote location places him directly in the path of unfolding dangerous events.

Ruth is Hugh Winchester's wife. She resides in an isolated cabin on Lake Morikawa, sharing a remote lifestyle that unexpectedly intersects with a criminal investigation.

Uma is a local store owner near Lake Morikawa. She operates the supply shop where Ethan occasionally stops, serving as a friendly face in the remote community.

Beth is the receptionist at The Anonymous Client, managing the front desk and scheduling for the successful virtual therapy platform.

Gayle is a journalist for the New York Times who visits Milwaukee to profile the rapid success of a newly established telehealth therapy platform.

Chip is the CEO of the Madison hospital where Ethan works. He approaches Ethan with news about his potential reassignment to a cold case, demonstrating the administration's awareness of Ethan's past career.