Jamie is a young boy living in New York City who possesses the unusual ability to see and speak to dead people. He views his supernatural talent as ordinary, often answering questions for ghosts who appear no different to him than living humans. He relies heavily on his mother for protection and understanding, though he soon realizes his abilities have practical and sometimes frightening applications.

Tia runs a successful literary agency out of New York City and provides a comfortable life for her son. She is deeply protective of Jamie and fears that his visions of the dead might be a sign of mental illness. When financial ruin threatens her agency, she makes questionable moral choices out of desperation, teaching Jamie early lessons about the flexible nature of truth.

Liz is an NYPD detective and Tia's girlfriend. She has a complicated dynamic with Jamie, occasionally buying him toys but also calling him "Champ," a nickname he dislikes. She holds conservative views that clash with Tia's liberalism, leading to frequent arguments. Her career in the police force is troubled, and she takes a dangerous interest in using Jamie's supernatural talent to solve cases.

Kenneth Therriault is a notorious serial bomber who terrorizes New York under the alias "Thumper." After dying, his spirit lingers in the physical world, possessed by a terrifying, alien force known as the deadlight. Unlike typical ghosts who fade away quickly, he retains a malicious will and begins to actively stalk and terrorize Jamie.

Harry is Tia's brother and Jamie's uncle. He suffers from early-onset Alzheimer's disease and resides in a care facility, sustained financially by Tia's literary agency. His deteriorating condition serves as a constant source of anxiety for Tia, who fears the illness might be hereditary.

Marty is a semi-retired Professor of Literature at New York University who teaches courses on Gothic mysteries. He lives in the same Park Avenue apartment building as Jamie and Tia. When he loses his wife's rings after her death, Jamie uses his abilities to help locate them, forging a unique bond between the young boy and the grieving academic.

Mona is Professor Burkett's recently deceased wife. In life, she was known to be somewhat obnoxious, a trait she carries into the afterlife by insulting Jamie's drawing. Her ghost provides Jamie with his first opportunity to prove his abilities to his mother by revealing the hidden location of her missing rings.

Regis is an agoraphobic bachelor and the highly successful author of the bestselling Roanoke saga. He is Tia's most lucrative client, single-handedly keeping her literary agency afloat. When he dies suddenly before completing the final, highly anticipated volume of his series, his ghost dictates the remaining story to Jamie.

Donnie is a wealthy drug lord who operates out of a highly secure mansion in Renfield. He controls a massive supply of narcotics and lives a life of extreme depravity and violence. His hidden stash of OxyContin makes him a prime target for those desperate for money and leverage.