Through the course of the investigation, Madsen and Soto learn that Hauser has been awaiting the prisoners' return for nearly 50 years. Soto will witness his life's work -- the history of Alcatraz -- come to life. Madsen will see everything she thought she knew about her family's past shattered, all while fighting to keep the country safe from history's most dangerous criminals. Then, 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 on the special two-hour series premiere.