The other protagonist, Sam is a 43-year-old patent lawyer dealing with the effects of her childhood trauma. She is often compared to her mother Gamma due to her logical and intelligent demeanor.

A 74-year-old criminal defense lawyer, Rusty is the father of Charlie and Sam. He is known for his commitment to defending alleged criminals and is seen by Charlie as a larger-than-life character with a jokey demeanor.

The late wife of Rusty and mother to Sam and Charlie, Gamma was an accomplished astrophysicist with a significant impact on her daughters. Her memory serves as a source of hope and inspiration for her family.

Present in both timelines, Judith is a middle-school English teacher and the complex perpetrator behind the crime mystery. She is initially seen as a nurturing figure to Charlie during her childhood.

A victim of the present-day narrative's crime, Kelly is a petite and vulnerable young woman who faces socio-economic challenges. She is caught in a complex web of exploitation and injustice.

The primary antagonist, Zach is a sadistic character with a history of criminal behavior. He has been a source of trauma for the Quinn family from the novel's past events.

Initially charming, Mason is revealed as an antagonist who was involved in the attack on the Quinn family. He is depicted as a morally ambiguous character with a complex relationship to other characters.