Tom and Diana are forced to cooperate with Dennis Ryland in order to find Gary Navarro of the Nova Group, and they soon discover that someone at the 4400 Center may be helping Gary hide out. Meanwhile, Shawn and Isabelle's relationship grows complicated.

Tom and Diana are drugged with a hallucinogen, created by a 4400, that causes them to confront significant people from their pasts.

Kevin runs for his life when he becomes a marked man because of his promicin research; and as Tom and Diana search for him, they discover the depths of his devotion to his work. Also, Shawn meets his idol at the 4400 Center.