Tom is startled when he awakens in an alternate world in which he's married to a new wife and Kyle is a well-adjusted medical student. Most jolting of all is his discovery that the 4400 don't exist there.

Tom and Diana pursue a 4400 who released a plague that eradicated a town's entire population and has powers that threaten to wipe out humanity. Also: a lobbyist from Washington, D.C., joins the 4400 Center to bring some political muscle to the movement.

When atrocities are linked to a 4400 with the ability to heal damaged chromosomes in utero, NTAC finds itself in a troubling international political cross fire. Elsewhere, Richard reunites with aging Korean War comrades; Diana accuses April of abusing Maia's power; and Shawn attempts to mend fences with his family.