Flashback: The Night of the Storm
The night the particle accelerator is set to start, Caitlin and her fiancé Ronnie are debating where to go on their honeymoon. Cisco warns Dr. Wells that a thunderstorm is coming in, but Wells seems unconcerned. Wells starts the particle accelerator, which it turns out Ronnie helped design and build. As Wells opens the champagne to celebrate, the champagne rises up out of the bottle before falling to the ground. Alarms begin to sound and it is clear that something has gone awry.
Cisco, Caitlin, and Wells realize the accelerator has to be manually shut down. Ronnie offers to do it since he is the lead engineer. Ronnie and Cisco get down to the accelerator and Ronnie tells Cisco that if he’s not back in 2 minutes to initiate shut down. Cisco refuses at first as there won’t be a way for Ronnie to get back, but Ronnie insists if Cisco doesn’t do it, everyone will die. After 2 minutes, Cisco shuts down the doors.
Caitlin runs down to the accelerator where Cisco tells Caitlin he had to lockdown the accelerator. Ronnie gets on the radio and tells Cisco he adjusted the accelerator so the energy would go up, not out. Caitlin tells Ronnie he needs to find another way out. He says the doors have to stay shut to protect her from the chain reaction. He then tells her that whatever happens, then there’s a flash and he’s gone.
After seeing a movie with Barry, Iris shares with Barry her continued fascination with “The Streak.” Barry tries to dissuade her from writing about The Streak, but she gets a call from Eddie. Right then, Cisco calls Barry to let him know about a car chase. Barry is off to stop the perp, handcuff him, and place him in the police cruiser, returning before Iris is off the phone with Eddie.
Elsewhere, there’s a crime family meeting taking place in a restaurant. As the head of the family is talking, a green smoke begins to fill the room. As each person inhales the smoke they die, and eventually the entire family is dead.
The next morning, Barry tells Joe that he helped the cops with the arrest. Barry confesses that keeping his secret is harder than he thought. They go to Barry’s office, and Joe shows him the box of evidence from his mother’s murder, promising to go through the evidence again. Eddie shows up to tell them that the Darbinyan family has been murdered.
At the crime scene, Barry realizes the family was poisoned with gas. Eddie says the door was locked from the inside. Joe says that there should be a canister, but Barry explains to Joe they all started in the same spot and should have been affected at the same time, which means the gas attacked them.
At Star Labs, the team is on it and they’re excited. Joe says that they’re going to need to come up with a place to hold meta-humans because they can’t keep murdering the people. Cisco suggests that the particle accelerator be modified to make it a prison.
Joe is watching the interview of Barry’s father following the death of his wife. Henry Allen explains that there was lightening in the house, and when it went away, his wife was dead. Eddie knocks on the door, clearly to see Iris, but Joe is home so he comes up with a shitty lie. Fools! Joe is a detective and he’s going to see right through your bullshit! Eddie suggests that they revisit the crime scene, and when Joe goes to get his jacket, Eddie tells Iris he’s tired of hiding from Joe.
At STAR labs, Wells tells Cisco they can use the copper cavities to contain meta-humans. They’ll have to counteract meta-human abilities, but he thinks it could work. Wells can tell that it’s hard for Cisco to be back in the particle accelerator, but Cisco attempts to play it off.
In Barry’s lab, Barry asks Caitlin about Ronnie and why she never talks about him. She says Ronnie wasn’t even supposed to be there that night; he was only at the party to support Caitlin. Before she can say anymore, the test results come back and it turns out there was no residual gas in the victims. However, there were two strands of DNA and Caitlin and Barry realize that the meta-human is the gas.
Just then, there’s a call that a woman is dead after a gas attack at the mall. Caitlin begs Barry not to go, but Barry is off. Barry arrives and finds the man in the hallway, and asks why he killed the woman. He responds that she deserved to die, and that he has one more name on the list. When Barry goes to hit the guy, he turns into smoke and gets into Barry’s lungs. Barry runs back to Star Labs, though he can barely breathe. He still has the poison in him and he tells them to extract it.
After he wakes up, Barry goes to see Joe to let him know about The Mist (so named by Cisco). It turns out the woman was a judge, so they are going through old cases to see who may have a motive. Joe and Barry begin to talk about Barry’s dead, and Barry suggests that he can break his father out of jail. Joe tells Barry that breaking his dad out of jail means that his dad would be on the run the rest of his life. Joe tells Barry that the suit means he can save some people, but he can’t save everyone. There will be guilt when he can’t save someone or when he makes a mistake. Joe tells Barry there are some things you can’t fight, that you just have to live with.
Barry goes back to Star Labs to talk to Caitlin. He tells her about his mother dying and how some days the pain he feels is the worse than the day she died. Caitlin tells Barry she’s been scared of going down to the particle accelerator, and he offers to go with her. Caitlin says that Ronnie saved lives that day and no one will ever know what he did. Barry says he knows and that Ronnie was a hero. Caitlin says she didn’t want Ronnie to be a hero, she wanted him to be her husband. I can’t tell if Caitlin and Barry are being set up to be a romantic thing or just really great friends.
Cisco comes down to the particle accelerator to tell Barry and Caitlin he figured out the gas is hydrogen cyanide mixed with a sedative. Barry recognizes that the sedative is one given to someone on death row. They do a search and find out that Nimbus was being executed the night of the storm. The reason his DNA wasn’t in the system is because he is supposed to be dead. Joe was the arresting officer on Nimbus’s case, and Barry realizes that Joe is the last person on Nimbus’s list. Before he leaves, Caitlin gives Barry an antidote she was able to develop in case the Mist got to him again.
Joe had decided to pay a visit to Iron Heights, the prison, to see Henry Allen. Henry wants to know why Joe is visiting him and Joe tells Henry he now knows he didn’t kill his wife. Joe tells Henry he is reopening his case and they will figure out who killed Nora. Joe apologizes for not believing him, but Henry says it’s ok because he always believed in Barry. Right then, the Mist shows up and kills the prison guard. He forms, and shows his identity to Joe. Henry watches the Mist infect Joe. Barry arrives, but he shakes his head so fast that his father can’t make out his face, though Henry recognizes the lightening from the night his wife was murdered. Barry uses the antidote and Joe tells him to go get Nimbus.
Barry confronts Nimbus in the street, and as he does so, Nimbus turns in to mist form. Wells tells Barry to keep the Mist coming at him as gas is the least stable type of matter, so keeping him in mist form will weaken him. Barry is sprinting, with the gas following him. After a few minutes of this, Nimbus reforms into human form. When Barry hits him, it knocks Nimbus out.
At the hospital, Barry tells Joe he could have gotten his dad out of prison that night, but he knows that wasn’t the right thing. Iris shows up with Eddie, and Barry leaves to let them talk to Joe. Iris begins to tell Joe that she and Eddie are dating, but he already knows (duh). Joe is pissed, but he tells Iris that it is going to be complicated. Iris tells Joe she likes him, and Joe says he’ll do his best not to shoot him.
At STAR labs, the Mist is in confinement. They’ve got a heavy-duty magnet containing him. Caitlin says they have to get used to working above a make shift prison filled with evil people with super powers.
Before they head back upstairs, Cisco wants to talk to Caitlin about the night Ronnie died. He wants to apologize. Caitlin tells Cisco she’s ok, and thinking about what Ronnie did to protect everyone made her love him more.
Epilogue: Wells is staring at the Flash suit when he flashes back to the night of the storm. Cisco radios upstairs to let him know that Ronnie saved the building by re-routing the system. Wells then goes into his super top-secret no-girls allowed room and watches the lightening strike Barry and says, “See you soon, Barry.” So did Wells plan for everything to go awry that night just to create The Flash?