The 4400, on USA Network
IMDb; TV Tango; TV Tropes; Wikia; Wikipedia

Caution: Spoilers!

Okay, so people from around the world have been disappearing for decades. Then one day in 2004, what appeared to be a comet changes course and accelerates toward the Earth. However, instead of crashing, it slows down, and rather than a comet, this glowing ball of light hovers above a lake at the base of Mt. Rainier, in Washington's Cascade Range. The light disappears, leaving 4400 abductees all at once, all together, near the beach. None of the returnees have aged nor have any memory of anything since they disappeared. The Department of Homeland Security forms a new division called NTAC (National Threat Assessment Command) to keep track of the returnees (who come to be called "the 4400"), and to investigate the mysteries surrounding them. The head of the Pacific Northwest division of NTAC (headquartered in Seattle) is Dennis Ryland. One of the teams he puts together to investigate the 4400 consists of Tom Baldwin (Joel Gretsch) and Diana Skouris. There's also a guy named Marco Pacella, who works in NTAC's theory room, who sometimes helps Tom and Diana by providing... well, theories, about the 4400. He also seems to be interested in Diana. Tom's son Kyle has been in a coma for the past 3 years, ever since a camping trip he took with his cousin Shawn Farrell, who disappeared. Shawn is back now, one of the 4400. Oh, and Tom's wife Linda eventually divorces him.

Sometimes we'll see random 4400s in individual episodes, but there are several main returnees that the series chiefly follows. It soon becomes apparent that some 4400s have acquired special powers, which may be helpful, or dangerous; and they can't always control their powers. Some returnees, however, don't discover any powers... at least not early on. Shawn has an ability to heal, but also to hurt or potentially kill, by draining people's life force. And when he heals, it drains him, so he has to rest afterward. At one point, he revives Kyle from his coma. Unfortunately, while Kyle has his memories, he doesn't feel anything about himself, his old life, his family, or anyone he knew. He comes to believe he isn't really Kyle Baldwin.

An 8-year-old girl named Maia Rutledge, who disappeared in 1946, sometimes has visions of the future. Eventually, she moves in with Diana. Meanwhile, the public begins to become more suspicious of the 4400, and some people even start killing returnees. A millionaire named Jordan Collier who disappeared in 2002, begins to organize his fellow returnees, building a housing development for them called Arcadia Estates. There's also an African American combat pilot named Richard Tyler, who had disappeared in 1951, while serving in the Korean War. He had had a relationship with a white woman named Lily Bonham, who happened to become the grandmother of another 4400, Lily Moore, who disappeared in 1993. Her husband Brian, who thought he'd never see her again, had remarried, to a woman named Carol, and never told their daughter Heidi (now 12, who'd been a baby when Lily disappeared) about her real mother. Richard and Lily eventually start a relationship together, and both move to Arcadia Estates, when Collier hires Richard as his head of security. And it turns out that Lily became pregnant sometime between her disappearance and the return. It later turns out that her baby is half black, so somehow Richard could be the father.

At some point, Washington, D.C. sends an agent named Warren Lyttel to the Seattle bureau of NTAC, and he ends up making trouble for Tom and Diana. He crosses the line when he takes Kyle into custody, but Tom and Diana later break him out. Tom wants to send him into hiding with Linda, but Kyle insists he has to go to Highland Beach, where Shawn had been abducted and he had been put into a coma, so they take him there. Tom ends up learning the truth about the 4400. It turns out Kyle is a channel for communication with those responsible for the abductions and the return. Major spoiler: the 4400 were taken by people from the future, and given abilities that will help change the course of history, because in the future humanity is dying out. And Tom is supposed to help the 4400. However, he can't learn more than that before Ryland, Lyttel, and other NTAC agents show up, and Lyttel disrupts the communication. Later, Kyle's personality returns, but he has no memory of anything that's happened since he awoke from his coma.

Elsewhere, Richard and Lily become concerned that Jordan is interfering too much in their lives, and is too interested in their unborn child (who he thinks of as a Rosetta stone for the 4400), so they run away. But not before the unborn baby somehow hurts Jordan, so he can't prevent Richard and Lily from getting away. And Shawn's little brother Danny attacks him after finding out his ex-girlfriend Nikki had started dating Shawn. In defending himself, Shawn accidentally nearly kills Danny, so, fearing his own power, he goes to stay at Arcadia Estates.

Season two
The story picks up one year later, and Diana adopts Maia. Eventually Diana's sister April will come stay with the two of them for awhile and start bonding with Maia, though April sometimes argues with Diana. Meanwhile, NTAC is now headed up by Nina Jarvis, who seems less cooperative with Tom and Diana than Ryland was. Richard and Lily, along with their baby, Isabelle, are still in hiding from both Jordan Collier and NTAC. (At some point Richard and Lily are married, though I'm afraid I'm not sure if this happened in season 1, 2, or in the intervening year.) It soon becomes apparent that Isabelle has various powers. Some are good, but some may hurt people or force them to hurt themselves, and Richard becomes worried about that.

Shawn is now using his gift to heal people, for the moment in a clandestine capacity, in exchange for donations to help Jordan open "the 4400 Center," a far more ambitious project than Arcadia Estates, which is also open to non-4400, promising to help them unlock their "4400 potential." Jordan and the 4400 Center will frequently be at odds with NTAC, as Jordan predicts a coming war between the 4400 and the rest of humanity (he kind of reminds me of Magneto, pretending to be Charles Xavier, but with a greater interest in PR and money). And while Shawn is now his protege, the two of them will have occasional disagreements, as well, though he still greatly respects Jordan. But Shawn also has to frequently heal Jordan, who's been having some kind of attacks ever since his earlier encounter with the unborn Isabelle.

Meanwhile, a psychiatric patient named Tess Doerner (Summer Glau), who disappeared in 1955, influences people (first fellow patients, then the hospital staff, eventually even NTAC agents) to build something she has visions of, which she thinks will let her communicate with the abductors of the 4400. It fails at that, but ultimately seems to cure a fellow patient named Kevin Burkhoff (Jeffrey Combs), who hadn't spoken in years. Before his breakdown, he'd been a famous neuroscientist, and now that he's cured, he'll become very important to the 4400.

Shawn gets involved with a homeless girl named Liv, and tries to help her out in various ways, though they don't always get along. Meanwhile, Jordan locates Richard and Lily, and convinces them to come to the Center, so he can prove he's changed. He says if his intentions aren't good, Isabelle will know it. After returning to the Center, one day Heidi comes to see Lily, having overheard her parents talking about her, and learning Carol isn't really her mother. But Isabelle doesn't seem to like Heidi.

Kyle starts college, where he meets a teacher named Wendy Paulson. He also begins having blackouts and experiencing lost time. At one point, Maia has a vision that Jordan will be killed. Shawn wants him to cancel a planned appearance, but he refuses. He also refuses protection from NTAC. He ends up getting shot and dying, though later his corpse disappears. Shawn inherits control of the Center, which seems to be more responsibility than he wants. His healing powers are also revealed to the public. And it turns out Kyle had shot Jordan during one of his blackouts. Later, a man named Matthew Ross shows up to advise Shawn in running the Center, but he may have ulterior motives, and doesn't always act in the best interests of the 4400s themselves.

Then there's an episode where things aren't as Tom remembers them. No one's ever heard of the 4400. They never returned, because they were never abducted, but went on living their normal lives. Maia is a grandmother; Richard's plane was shot down in 1951; Jordan Collier is alive, and governor (though we don't see him in the ep). Kyle was never in a coma, and ends up going to medical school. Shawn is also doing well, and Danny and Nikki get engaged. Tom, meanwhile, has been married for two years, to a woman named Alana Mareva, who disappeared in 2001. But Tom has no memory of ever having met her. However, none of this is real to her either, and she says she's a 4400. She can find no trace of the life she remembers. But they have to go on pretending all this is real, for the benefit of everyone else, and they eventually come to love each other. The only problem is that, occasionally, Tom sees a mysterious door appear, with some strange lab behind it, but to everyone else the door looks normal, and leads to like a storage room or whatever. This happens in the Jordan Collier Museum, which in Tom's reality was the 4400 Center. But after awhile, he stops seeing the door. Eight years later, Tom is promoted to Jarvis's position at NTAC, and Alana becomes director of the museum. On their 10th anniversary, they renew their vows, so it finally seems real to them. But then Tom sees that door again, goes through it, and learns that Alana is responsible for creating this fantasy world, though she's unaware of it. The people from the future had used her to give him this relationship to help him face the personal crisis that is to come. He convinces her to put an end to the false reality, but the two of them then meet in the real world, remembering their fantasy years together, and start a new relationship.

Back in the real world, Kyle regains memories from his blackouts, and tries to hide the truth from everyone. But later someone else is arrested for shooting Jordan, so Kyle wants to confess. And Burkhoff goes to work at the 4400 Center. And at some point there's a disease affecting the 4400, which robs them of their powers, and could potentially prove fatal. And Ryland returns to NTAC, temporarily. He wants to quarantine all the 4400s, but the 4400 Center opposes this idea, and gets ready for a fight. They encourage affected 4400s to report to quarantine, but suggest non-affected 4400s might not want to do so. Some who do go into quarantine include Shawn (who turns control of the Center over to Richard), as well as Maia and Alana.

Meanwhile, Ross has been having the Center's doctors do tests on Isabelle without Richard and Lily's permission. Lily is upset when Richard seems too accepting of what the Center was doing to Isabelle, and also she doesn't want to get involved in a fight between the Center and NTAC. So Brian helps her and Isabelle leave the safe house they'd been staying at. And Burkhoff wants to share information with NTAC, but they don't want to share with him. Marco gets NTAC's classified medical documents to him, though. He eventually learns about an inhibitor in all 4400s, which Ryland had ordered an NTAC doctor named Matt Hudson to create soon after the 4400s first appeared, when some of them were causing trouble. It was to inhibit a neurotransmitter in them called promicin, which gave them their abilities, but the inhibitor was also responsible for this disease. Actually, as Burkhoff insisted, not a disease, but a side effect. The promicin inhibitor is the reason not all 4400s have yet developed powers, even though it obviously didn't work on everyone. Eventually Lily takes Isabelle back to the safe house, when it becomes apparent than Isabelle wants to go back. Burkoff creates a serum to neutralize the inhibitor, using Isabelle's blood. The cure is given to Shawn, who then helps heal others, though not before at least 23 of the 4400 had died of the "side effect."

Later, Kyle confesses to Shawn that he shot Jordan during a blackout, and Shawn ends up draining his life force... but instead of killing Kyle, this just expels the presence from the future that had been possessing him. Other things that happen in the season 2 finale include Marco apparently starting a relationship with Diana, Ryland and others being arrested, Jarvis reassuming command of NTAC, Richard discovering telekinetic powers, Tom going with Kyle to turn himself in to the authorities, a fully grown and naked Isabelle going to see Shawn, and Jordan Collier appearing at the Mt. Rainier beach, apparently returned from the dead. Also, Maia said that the war is just beginning.

Season three
Lily ages rapidly and dies of old age, apparently as a result of Isabelle having grown up overnight. Isabelle, meanwhile, learns just how powerful she is, and that she's pretty much indestructible. A major focus of NTAC's concern this season is the Nova Group, who profess to be peaceful, but who could pose a threat to the government. Also, Shawn and Isabelle start a relationship, which will soon become romantic, which Richard is not happy about. Also we learn that there is a rival faction in the future who are trying to stop the plan of the people who placed the 4400 in this time and gave them their abilities. And Isabelle is a part of the rival faction's plan to stop the 4400, so the first group from the future wants Tom to kill her, with an injection they provide. Burkhoff begins experimenting with promicin, and injects himself with it, and develops the ability to heal himself. This makes him a target of NTAC, and he and Tess go on the lam. A group working for Ryland gets promicin from Isabelle's blood, and they begin injecting soldiers with it, to serve as a deterrent against the 4400. Jordan Collier reemerges, and he, Tess, and Kevin steal Ryland's promicin supply, intending to give shots of it to anyone who wants it. We also learn that anyone who takes promicin injections will have a 50/50 chance of either developing 4400 abilities, or dying. As Isabelle becomes mentally unstable and a threat to everyone, Richard is forced to use his telekinesis to inject her with the shot the future gave to Tom. Also, Alana is forced to go into hiding because of an involvement with the Nova Group. Oh, and Diana and Marco broke up, but they remain friends. April shows up with a boyfriend named Ben, who Maia had a vision of with Diana in the future. Diana and Ben try to avoid this future, but eventually they start a relationship, as much as they hate to hurt April.

Season four
Many people are taking promicin shots, despite the chance of death. NTAC is very upset about this. Shawn is in a coma. Diana, Ben, and Maia are in Spain, trying to stay away from all the stress of NTAC and everything. But before long, of course, Diana and Maia go back to Seattle. Kyle returns from prison, and meets a girl named Cassie, but she turns out to be a mental manifestation... a 4400 ability he developed after taking a promicin shot. She'll serve as a guide to him, telling him things he needs to know or do. Isabelle is in prison, without her abilities. Kyle injects Shawn with promicin, to wake him from the coma. Jordan reveals his ability- he can remove promicin from people's system, thus taking away their abilities, ironically. Cassie leads Kyle to an old book which contains a prophecy about Jordan, the messiah of a cult founded in 1918. Also NTAC has a new leader, Meghan Doyle, who eventually starts a relationship with Tom. Isabelle eventually escapes custody. April gains a 4400 ability. We also learn that there are people (or at least their minds) from the rival faction from the future, inhabiting the bodies of prominent individuals in the present, to work against the 4400. They're called "the Marked." Matthew Ross was one of these possessed people, and the mind that possessed him is later implanted in Tom (though it is some time before it takes him over). Kyle brings the book about Jordan to Jordan, who accepts his destiny to bring Heaven to Earth, and a cult grows up around him. They eventually take over part of Seattle, and rename the area "Promise City." Isabelle joins them. Shawn reopens the 4400 Center, and also considers running for city council. Burkhoff develops a test that would determine in advance whether a person would survive a promicin shot or not. Tom, being controlled, eventually reactivate's Isabelle's powers, to use against Jordan. Diana and Meghan become suspicious of Tom, and find a way to remove the entity controlling him.

Of course, I'm intentionally leaving out lots of things, and also forgetting lots of things. Um... and um... I guess the series was cancelled, which sucks because I think there's a lot that hasn't be resolved. But in any event, it was a very interesting show. I should probably say more, but I dunno what.....