As 4400 members begin to pass away from the illness, Diana and Tom discover that the very agency that they work for may be responsible for this illness in the first place. Meanwhile, Lily takes Isabelle on the run from everyone, including Richard. Alison reaches out to Kyle for help when it begins to look like Marsden will be convicted for the murder of Jordan Collier, putting Kyle in the position of either telling the truth or letting an innocent man get life in prison.