While investigating a homicide, Detective Rebecca Madsen discovers fingerprints that belong to a former Alcatraz inmate, who was believed to have died decades earlier. A family past with the prison makes her especially interested in the case, so she turns to an Alcatraz expert and comic-book enthusiast, Dr. Diego "Doc" Soto for help piecing together what happened. Together, they discover that the suspect is alive and appears not to have aged since his incarceration and that soon he will be joined by other former inhabitants of the prison.