“The Flash Reborn” is episode one of season four of The Flash.
It’s six months since Barry went into the Speed Force prison in the season three finale, “Finish Line”. Wally, Cisco and Joe are hunting for a teleporting meta, whilst Iris runs operations from S.T.A.R. Labs. She works out the jumping pattern, Cisco and Wally ambush the teleporter and she’s finally surrounded by the police and stunned. Back at S.T.A.R. Labs, Iris isn’t so impressed with their performance. 1 in 3 metas are getting away. Cisco thinks they’d be better off if they weren’t a man down.
Iris is having dinner with Cecile and her father. When Cecile leaves the room, Joe tells Iris that since Julian moved back to London, they’re short-staffed in the crime lab. He’s been stalling, saying Barry is on sabbatical, but they want to replace him. Iris says they should; Barry isn’t coming back. Joe suggests they have a funeral.
Iris returns home, only to be disturbed by an explosion and something flies past her windows. She calls Wally and Cisco and a figure clad in samurai armour lands in front of them. It turns out Wally speaks Japanese. The samurai wants the Flash. Wally says he is. The samurai says he isn’t; he wants the best. Bring him the Flash or the city falls. Cisco asks what the samurai thinks he can do against them with a sword. A stupid question; the sword is plunged into the ground sending a powerful shockwave of energy out. The samurai says if the Flash doesn’t face him in one day, Central City falls.
Back at the labs, Joe says the Flash isn’t there. Cisco asks what if he was. They’re trying to keep the city safe and barely managing it. Without the Flash there will be serious damage. They need to bring Barry back. It’s pointed out that the reason Barry is in the Speed Force prison is because otherwise it would destroy the city, the whole world. Cisco asks what if he can solve that. He’s been working on this ever since Barry left and has consulted with a lot of people. He thinks he’s finally figured out a way; just needs a couple more things. Iris wants them working on a plan to defeat the samurai instead.
Cisco goes to find Caitlin, who is tending bar. As Caitlin, not Killer Frost. She says it’s just her. Cisco wants her to come back; she knows Barry is in the Speed Force prison. He needs her help and they need Barry to stop the samurai from blowing up the whole city. Caitlin agrees.
Iris arrives at the labs to find no-one else there. She traces the S.T.A.R. Labs van, which is at the airstrip they’ve used for tests. Cisco tells Wally and Joe they can get Barry back. Then Caitlin arrives. Cisco explains how, by using the Speed Force Bazooka and some other stuff, they can get Barry back. They try, and nothing happens as Iris arrives.
Elsewhere, however, a portal opens, and someone speeds out, going many miles before stopping. Barry. He collapses.
Cisco has managed to get Barry back, but he’s not in great shape. He’s not speaking coherently and they don’t know what’s wrong. He’s certainly not in any sort of shape to fight the samurai, even if he does have his powers.