Richard Tate, a mental patient at Bridgeview Criminal Hospital, goes berserk and escapes.
Caffrey and the team believe he's infected because he tore through a 9,000-volt electrified fence, and his room has drawings of forest made of glass trees. The drawings reflect the same dreams Caffrey, Lucas and Cavennaugh have been having.
Going through Tate's files, Caffrey and Cavennaugh learn he had been diagnosed as a paranoid schizophrenic after he allegedly murdered his family because he thought they were aliens and he burned down the house.
Fenway examines the electrified fence Tate went through and sees Tate had left some blood from a cut he received as escaped.
Lucas asks J.T. to sign off on some weapons suggestions by Caffrey. Caffrey interviews a Mr. Miller, another patient and friend of Tate. She receives relatively no information except that Tate saw a vision of aliens coming prior to his escape.
Fenway gives the good news that none of the other patients have any alien DNA.
Tate visits the house of a single woman and abducts her.
Lucas chats with his fiancée, Rachel, and they discuss wedding plans. J.T. offers to bring Rachel a little closer to Lucas's area, since Lucas won't be able to go home for a while.
Fenway examines the blood sample and learns it is not Tate's blood. Caffrey now believes it's another infectee, probably one of the crew from the Big Horn.
Tate is now chipping away at the floor of the young woman's house, but leaves because he doesn't have the correct tools to do enough digging. The infectee now appears, and the team later identifies him as Lieutenant Raymond Novak from the Big Horn.
Cavennaugh receives a call that Tate has been spotted; Tate is eventually taken into custody. Fenway checks out Tate and gives him a clean bill of health. Although Tate may have had some small signs of the alien signal as a child, they are insignificant except for his nightmares. However, Tate's story about his escape is vastly different from hospital's report. It was not Tate but Novak who murdered a guard and an orderly. Novak had tried to abduct Tate, and Novak went through the electrified fence. Tate was able to get away somehow and Novak had been stalking him since.
Caffrey and Cavennaugh hear an audio tape testimony of Tate as a child while he was being interrogated for the alleged murder of his family. After exhuming the body of Mrs. Tate, they see her bones have mutated. Caffrey speaks again with Tate and Tate gives her the reason Novak tried to abduct him. Novak is looking for a special alien artifact, which is the object that had made Tate's family go crazy and mutate 26 years earlier. However, he gives the wrong location. Ramsey peruses drawings Tate made and is able to track down the exact location. However, Novak has discovered the object before them.
Cavennaugh's team arrives just in time. Novak tries to make a run for it, but is gunned down. Back at the Threshold lab, Lucas gives his own analysis of the alien object. Caffrey and J.T talk, and she mentions that this object has to be a 100 years old. Caffrey has one more talk with Tate, and tells him that he'll be transferred to a better hospital and that what he did to his family back then was the right thing to do.