Years ago when the most dangerous prisoners of Alcatraz mysteriously disappeared, they resurface in the present day as part of a larger conspiracy, leaving a police detective, an expert on Alcatraz and an FBI agent to track them down.

When a sniper begins targeting young victims, the team is forced to retrace the steps of the past in order to solve this modern day mystery.

When child killer Kit Nelson, a terrifying kidnapper who always returns his victims home - after he's killed them - reappears from the past, the team is in a race against time to catch the man before he kills again.

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.

Rebecca, Doc, and Hauser set out to capture musically-inclined serial killer Webb Porter, an unknown ’63 that returns more violent than ever.

Doc and Rebecca close in on a man who may be the key to revealing the secrets behind all the returning criminals. Meanwhile, Hauser makes a discovery beneath the halls of Alcatraz that brings him ever closer to the truth.