In a broadcast, the Nova Group promises the world a demonstration of their power on October 19. Tom and Diana apprehend Gary, but he refuses to give any information about October 19. Meanwhile, it's learned that Shawn has been funding the Nova Group for months, unaware of their murderous intent. Meanwhile, Shawn helps Isabelle deal with the guilt of her mother's impending death. Lily dies peacefully. Written by Amjad (Helsinki, Finland)

It seems that earlier that morning Tom entered an NTAC interrogation room and shot TJ Kim. In the end, Boyd Gelder is apprehended and Tom is able to clear his name. Meanwhile, Richard undertakes a journey to release Lily's ashes, and Diana discovers that Kevin Burkhoff, who has been injecting himself with doses of promicin, has developed a 4400 ability. Burkhoff can, sometimes, heal his body. In the closing scene we see Isabelle and Shawn kissing. Written by Amjad. (Helsinki, Finland)

Tom and Diana must hunt down a kidnapper who targets 4400 children. Maia's sister, Sarah appears.

Tom and Diana track down the 4400 children kidnapper.

Daniel Armand of The Nova Group launches an attack against Shawn causing mental illness. Isabelle seeks retribution. Alana tracks down a drunk driver responsible for the death of her husband and child.

Tom and Diana pursue the last member of the Nova Group, Gary Navarro but are foiled when he receives a tip off to escape capture. Alana is detained to explore suspected links to Nova Group.

Tom and Diana are drugged by a 4400 and are forced to face some unresolved issues from their past. Isabelle decides that Shawn should marry her.

Dr. Burkhoff continues his experiments on himself and forces them on another person and Maia has a nightmare where Diana looks like a monster. A rock star tries to involve Shawn in his health that demands almost all of his time.

A serial killer aims at people with a certain chromosome and Shawn gets a 4400 wedding cigar.

Just as he's about to be wedded to Isabelle Shawn has seen Jordan Collier very alive and helps NTAC to search for him. April presents her new boyfriend to Diana, but soon after Maia tells Diana about a family enlargement.

The Nova Group escapes from prison so Ryland decides to develop his troops at the fastest and most ruthless possible.

Jordan Collier's strategy is spread out 4400-abilities to everybody who wants them, and Devon is eager to be the first to try.

The 4400 explores the travails of the 4400 people who all at once returned in a ball of light to Earth; though the returnees had not aged physically, many of them reappeared with dramatic abilities ranging from enhanced reflexes to precognition. NTAC (National Threat Assessment Command) is the government agency responsible for keeping track of the returnees and investigating all things related to the 4400. Written by ahmetkozan