A 4400 terrorist marks the dead Jordan Collier's birthday by planting a device within NTAC that causes all the males to turn savage, forcing a lockdown of the facility. Meanwhile, Lily suspects the 4400 Center has devious plans for Isabelle; Shawn adjusts to being a media figure; and Kyle kindles a romance.

Tom and Diana discover that the source of the disease that threatens the lives of the 4400 is linked to a conspiracy to inhibit their burgeoning abilities. Meanwhile, Lily experiences harrowing hallucinations; Richard organizes resistance to the quarantine; and Kyle decides to own up to the Collier shooting.