Guy Hastings, an Alcatraz guard, reappears. Although a good man, Hastings is being asked to do bad things and will come face-to-face with an old acquaintance.

Madsen and Hauser hunt down Johnny McKee a former Alcatraz inmate and vicious killer with a background in chemistry. It's a race against time before McKee horrifically poisons more innocent victims. Meanwhile, more details emerge about Madsen's grandfather.