The plot of the story is basically, this woman (Prairie) has been missing for 7 years. She shows back up on a bridge which she then leaps off of, it being captured on video. Her parents receive a phone call that it may be their daughter. They go to the hospital and Prairie says, "Who are these people?" Cue her mother putting Prairie's hands on her face (and saying "mom?"), and the father says she's never seen us cause she was blind. Oh, and she doesn't recognize her name, and instead wants to be called "The OA." The real interesting part is she gathers up these 5 people, and she's telling her story.
She claims she was the daughter of this rich Russian guy (oil tycoon) and she gets these weird premonitions. She has one about drowning, and sure enough, eventually her and a bunch of other rich kids have their bus go off a bridge and they all drown. She goes to some weird starry looking place and this woman asks her if she wants to go back, which she replies yes; the caveat being she has to give up something, which is her sight. She gets adopted by the above family (not before some other shit that doesn't matter much).
Prairie starts having premonitions about meeting her (now dead) father again on her 21st birthday at the Statue of Liberty, so she runs away to NYC. Her father doesn't show, so she starts being a hobo and playing violin in the subway. Some guy approaches her and asks her if she died and came back to life. Mind fuck begins. He says he does research on near death events (NDE's) and convinces her to come with him to participate in his study. Unfortunately she gets there and realizes she's been abducted and there are other prisoners there. It's a kind of awesome setup; the guy builds a compound at some abandoned mine area far from civilization. Underground he builds his prison with a small stream that runs through it, and these plexiglass cells that are all adjoined. Over time she gains his trust (because she's blind) and tries to poison him, another prisoner is dead, yada yada and a bunch of other shit happens. Prairie also escapes at some point, but when she realizes she's trapped by the fact that this place was built around a mine, she gets smacked in the back of the head by her captor (goes by 'Hap'). Aaaaaand, she gains her vision back. But Hap doesn't know this. The fucky part starts now too though, because while she was dead from the smack to the head, she eats a fucking bird that I guess teaches her dancing.
Every couple weeks one of them gets gassed. They eventually figure out that it's just something to make them forget, so they devise a way to suck the air from the intended victim's cell so that the person remains conscious. It's at this point that they learn the guy is putting them in this contraption that fills with water to drown them, because these people don't die and he wants to know where they go. This takes dozens of attempts though, each time with these people drowning over and over. Homer, one of the prisoners, is the one that gets drowned the most. Prairie tells him to eat something alive to bring it back when he dies. He finally remains conscious enough and in his death he eats a fish....and learns to dance.
One of the other guys I guess is sick for some reason and says that if Hap takes him again, he's not coming back. He's taken to the experimental machine where he begs for his life with information. He tells Hap that Prairie can see now. The experiment goes wrong, dude dies, and Hap dumps his body in the cell while yelling at the others that they did this, and he's pissed about Prairie lying. For some reason, Prairie and Homer start doing their two dances together (apparently for 11 hours), and the dead guy is revived. They figure out that they're angels, and they call Hap the "Angel Hunter." Prairie thinks that the 5 dances (can't remember why she thought 5) are the key to opening a portal to an alternate dimension. Now they play the waiting game.
Hap finds a 5th prisoner, but she doesn't want to come. He forces Homer to come along to seduce her. Plan: success. Eventually 4 of the 5 of them die and learn their dance move. The 5th prisoner never gets one. Hap has been watching the prisoners and realizes what's up, and he learns the dance moves too.
Eventually the sheriff comes and Hap has headphones on and doesn't hear him enter the house. He's immediately arrested, but Hap convinces him that his captors perform miracles and can cure his ALS ridden wife. Dumb shit sheriff drives him off like he's being arrested, but instead picks up his wife to bring back to Hap's dungeon of angels. Prairie and Homer do their fucky dances with the sheriff's wife and she wakes up saying that she has the 5th and final dance. Homer and Prairie hug and Hap loses his shit, killing the sheriff and his wife, and then takes Prairie to the middle of nowhere and drops her off, saying that she'll never find her friends again.
That kind of summarizes the 7 years. In the present, she's trying to teach these 4 kids and their teacher the dance moves so that they can open the portal for her. Most of the shit in the present day is fucking retarded though. One of the kids, in the final episode, breaks into Prairie's house in the middle of the night and finds a bunch of books that seem an awful lot like she drew inspiration from them (Homer's 'The Illiad,' a book about NDE's, and some other shit). Prairie had been seeing an FBI psychologist, and for some reason he's also in the house and stops the kid. Then hugs him. None of this shit makes sense. And then we get that finale scene, where the kids do the fucky dance and apparently save the day.