A girl Jack's age who exudes a fearless demeanor and becomes Jack's ally in the search for his father. She deals with her own feelings of guilt and isolation stemming from the loss of her parents.

Jack's hardworking mother, who struggles to provide for him in a large city after separating from her husband. Her dedication goes largely unrecognized by Jack, who views her through a narrow lens.

Jack's emotionally unstable father, previously a successful scientist who is now estranged from his family due to personal and professional turmoil. He becomes a focal point of Jack's quest to understand their family dynamics.