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Caution: potential spoilers.
Okay, a few preliminaries. First, this show is based on a novel I've never read, though I gather there are some differences. Also, I should say that well before it even premiered, the show drew frequent comparisons to Lost, for its mind-bendiness, or whatever. Also, it has some actors who were in that show. Anyway, the premise is, on October 6, 2009, at exactly the same time, everyone in the world blacks out for exactly 2 minutes and 17 seconds. During that time, most people had visions set at the same time, 10pm (Pacific Time), April 29, 2010 (or whatever time and date corresponded in other time zones). Of course, it's not like time froze during their blackout, so there were disasters around the world, with no one conscious to control cars and planes that were operating at the time; patients died in hospitals, etc.... all sorts of things went wrong, with no supervision, which means not only lots of deaths, but lots of damage. So it takes awhile for emergency services to deal with everything. But even once the immediate crisis passes, there remains the question of how this happened, how it's even possible, who, if anyone, was behind it, and why it happened....
At the time of the flashforward, an FBI special agent in L.A., Mark Benford, was pursuing terrorists with his partner, special agent Demetri Noh. In Mark's vision, he saw himself investigating the event everyone was experiencing. He also had a sense that someone was coming to kill him. And... well, he's a recovering alcoholic, and in his vision, he was drinking again, which worries him, because his wife, Olivia (who, btw, played Penny on "Lost") has said that she would leave him if he ever started drinking again. So, he leaves out that part of his vision, when he talks to her about it later. Anyway, when he regains consciousness in the present, everything is confusion, and it takes awhile for everyone to put together the fact that this phenomenon was global, that everyone had visions during the "blackout," and that everyone's visions were of the same point in the future, and that the visions seemed pretty consistent (for example, one FBI agent had a vision of a meeting with someone in London, and she had the same vision; others remembered reading the same things in newspapers in the future, etc.) So, Stanford Wedeck, assistant director of the L.A. office of the FBI, sets up a task force (so far including Mark, Demetri, and Janis Hawk) to investigate the incident. (The case will be called "Mosaic," also the name of a website they set up for people around the world to share their visions.)
Demetri has trouble accepting the flashforwards everyone has had, because he didn't have any vision, which makes him think six months from now, he'll be dead. Olivia Benford (a surgeon) is upset because in her vision, she was in love with another man, who at the time, she'd never seen before, but she's positive she'd never cheat on Mark. Janis had a vision in which she was pregnant, though she's not right now, and isn't even seeing anyone (and it isn't long before we learn she's gay). There's also Aaron Stark, another recovering alcoholic, who is Mark's sponsor and friend. His daughter, Tracy, was a marine who was supposedly killed in Afghanistan. Her remains had been identified from DNA, but there wasn't enough left of her body to recognize. However, in his vision, she's alive, so he's determined to find her. There's a surgical intern named Bryce Varley, who just before the incident, was thinking of killing himself. But since he saw that he's still alive 6 months from now, he seems to think there's hope, and sees the flashforwards as a gift from God. (In his vision, he was talking with a Japanese woman named Keiko Arahida, and he becomes determined to find her.) There's a 19-year-old student named Nicole Kirby, who works as a babysitter for Charlie Benford, Mark and Olivia's young daughter. Her vision made her believe the flashforwards were punishment from God (she thought someone was drowning her, and she felt as if she deserved it). Meanwhile, Charlie's vision was apparently a bad dream, in which "there were no more good days." (We eventually learn more about her flashforward.)
Anyway, Mark and Demetri begin setting up a corkboard with some index cards tacked up of names and things Mark saw in his vision, even though he has no idea what any of it means. (Also, his vision was fuzzier than most people's, apparently because he was drunk in it, though it's some time before he tells anyone that.) It does make one wonder, if that stuff could have been there in his vision just because he had put it up because of having seen it... in his vision. (Cause and effect get kind of muddled, in a show like this.) The first real lead comes when Janis, having watched tons of surveillance camera footage from around the world, sees a stadium in Detroit where, while everyone else was unconscious, someone was walking around. This person becomes "Suspect Zero," and the Mosaic team spends a long time trying to figure out who it is.
Before long, Olivia meets Lloyd Simcoe, whose son Dylan is in the hospital. Lloyd is the man from her vision (and Dylan was in Charlie's vision). For a long time, Olivia wants to try to avoid him as much as possible, but they do slowly grow closer. Meanwhile, the Mosaic task force begins looking into a suspect called D. Gibbons, though they don't know who that might be. Also, Demetri learns that someone else's flashforward provided her with the knowledge that he was going to die on March 15. He tried to keep the fact that he believed he was going to die from his fiancee, Zoey Andata. Her own flashforward was of walking on the beach, at a service she believed to be their wedding day. Also, one of the terrorists Mark and Demetri had been pursuing just before the blackout was a woman named Lita; she's now in prison, and Zoey is her lawyer. She seems to have ties to whoever's behind the blackout.
Eventually there is a startling event that proves flashforwards don't have to come true (but I won't spoil what that event was). And after awhile, there's some question as to the Mosaic task force's authority to take the lead on investigating the blackout. I guess it eventually becomes inter-departmental, mainly including the addition of CIA agent Marshall Vogel. Also, Aaron begins to learn about the truth behind Tracy's supposed death in Afghanistan, which involves a group called Jericho. We also meet a man named Simon Campos (who played Charlie on "Lost"), a scientific partner of Lloyd's, and the two of them announce on television that their experiment caused the blackout, though they didn't foresee that happening. The two of them assist the FBI in its investigation, though no one really trusts Simon. We also eventually learn that Simon was involved with the group that was really behind the blackout, though he doesn't know much about them; they've simply been using him for years without him knowing it. Now they've kidnapped his sister Annabelle, to ensure his continued cooperation. The Mosaic team eventually learns that "D. Gibbons" is actually a man named Dyson Frost, who had been conducting smaller-scale flashforward experiments for years, both on himself and on a number of subjects. One such subject was a savant named Gabriel McDow. Olivia and an FBI agent named Vreedle try to find him, and he eventually reveals that he's had many flashforwards, and that in all of them, she had been married to Lloyd all along, not Mark. Eventually, the task force's investigations lead them to a man named Lucas Hellinger, who they arrest... but there are still others higher up in his organization, and he seems confident that nothing can prevent the future he's foreseen. Mosaic also uncovers a "quantum entanglement device" in the form of a ring that, if worn, will keep a person awake during a blackout.
Well... eventually April 29 arrives, and... eh, things aren't precisely as they were in flashforwards (for some people things are completely different). But alot of things are remarkably similar, though what it all means may be different than expected, and it may not all play out the way one would have thought, after the the foreseen 2 minutes 17 seconds have passed. But I do think it was all very interesting, some of it quite moving. And it all ends with a second blackout, set years in the future. There are lots of cliffhangers needing to be resolved, and I'd like to see what happens after this point, but I don't believe the series is going to continue, unfortunately. Still, while I thought some episodes were great, others were pretty "meh." I think the show would have done better if it had less episodes and the story moved at a faster pace. But overall, it was pretty good. Not sure what else to say, except that I should mention I've avoided a ton of spoilers (also, I'm sure I must've mentioned some events in the wrong order)....