Rogue Air opens with Harrison Wells telling Eddie Thawne that he will reclaim everything that was taken from him in life.
Across town, Iris meets with Barry at the coffee shop. Barry promises that they’ll find Eddie, who’s still held captive by Wells. Barry then gets a call from Cisco, and goes to STARR Labs. At the Labs, Cisco informs the team that Wells’ wheelchair hid a a high-tech power source. He surmises that the source acted like a battery, charging Well’s speed whenever he sat in it. Then, the team gets a read on Wells’ energy signature deep within STAR’s basement. Joe, Cisco, and Barry go to investigate.
Following the signal, they uncover Wells’ secret location. Barry pursues Wells across the city, but can’t catch him. In the chaos, Wells releases Peek-A-Boo from her cell. She almost kills Caitlin, but Iris saves her and subdues Peek-A-Boo. They then hear Eddie’s cries for help and locate him in a catacomb below. As Eddie is carried off to recuperate, Iris finds Eddie’s engagement ring, meant for her, laying on the floor.
Barry returns to find Eddie safe and sound. Eddie tells the group that he and Wells are related, and that Wells’ real name is Eobard Thawne. Eddie describes the “futuristic tube” that Wells was developing underground, and how it was the “key” to Well’s return to the future. Cisco then identifies the tube as a futuristic power source that will re-power the particle accelerator. The power source will reach its full power in 36 hours, and will reignite the particle accelerator then. The group knows that the accelerator’s energy will kill the metahumans stored in STARR Labs, and decides to send them to the prison island of Lian-Yu, where they’ll be safe. Barry says he’ll need Joe’s help in transporting the metahumans.
Joe goes to his boss at Central City’s Police Department and asks her to clear the roads for the metahuman’s shipment. She says she can’t get involved, citing the numerous laws that Joe and gang have broken by imprisoning the metahumans without due process. Barry meets with Joe and says that ARGUS can help transport the metahumans to Lian Yu, but they still need immediate support in Starling City. Without CCPD out of commission, Barry decides that the only man he can turn to is Captain Cold.
Barry confronts Cold at a bar. Cold says he won’t help Flash usher his enemies out of town, saying that it’s not his problem. Barry eventually convinces Cold to help him, but with a price. Snart says he’ll think of an acceptable price and come back to Barry with one once he decides.
Across town, Iris finds Eddie at the CCPD. There, Eddie says what Wells told him: That Iris will marry Barry instead of Eddie. Accepting that it is not his fate to be with Iris, he breaks up with her and leaves.
At STAR Labs, Snart confronts Barry and gang and gives his price. In exchange for his help, Snart demands that every record and file on him be permanently erased. Barry accepts, but Joe protests. Barry argues that he’ll do whatever it takes to save the metahumans’ lives. Before Joe can further protest, Flash races to the CCPD and digitally erases every file on Snart. He then brings all physical evidence to Snart, who destroys it with his Cold Gun. Then Snart’s sister, Golden Glider, appears, and the team-up officially begins.
Barry brings Cold and Glider back to STAR Labs. Cold tells Joe that he can be trusted, while Glider tries flirting with Cisco again. Cisco is tempted by her charms, but resists. Cisco then shows how they’ll get the Metahumans out—via a commercial 18-wheeler that’s been retrofitted with Wells’ secret power source. Cisco reverse-engineered it so that instead of powering the metahumans, the source will weaken them. After knocking the metahumans out with gas, the gang ships them across town. Unfortunately, the metahuman prisoners wake up in-transit.
When the truck stops at the ARGUS meeting-point, the group gets ready to make the switch. Cold’s sister asks Cisco for her own superhero name, and he (kinda) reluctantly dubs her as Golden Glider
Inside the truck, the power damper fluctuates and the metahumans regain they powers. They break out of the truck and attack Flash, the gang, and Cold. A massive brawl ensues. The Rogues almost kill The Flash, but Captain Cold and Glider even the tides. Cold says that they should just call the night a “draw,” and allows them to escape. Now indebted to Snart, the inmates flee. Flash then realizes that Cold rigged the power damper and turned the situation to his advantage. Now with an army of Rogues on his side, Cold leaves the Flash alive and says that he “owes him one” too.
Back at STAR Labs, Barry guilts himself for trusting Snart. He compares himself to the Arrow, saying that Oliver Queen could have brokered the situation. Joe tells Barry that he’s not the Arrow, and he knows better than to cross the line between right and wrong. Joe makes Barry promise to walk along the dark side, and Barry agrees. But then, Well’s particle accelerator Barry reaches it full point.
At the CCPD, Iris tells Eddie that despite what Wells said, she will continue to love him. Eddie argues back by saying that he always knew that Iris loved Barry, and is at peace to let her go. Iris agrees to break up with him, and the two go their separate ways.
When Wells returns to STAR Labs, Barry confronts him outside. Wells says he’ll show Barry why he needs the Particle Accelerator again, but Barry isn’t about to be fooled twice by his enemies. As the two prepare to clash, Firestorm and Arrow arrive assist The Flash.
Wells puts on his Reverse Flash uniform, and a massive super-powered fight erupts. Arrow hits Reverse Flash with a nanite-powered arrow, which momentarily drains Reverse Flash of his speed. From there, Arrow and Reserve Flash enter a normal street-brawl.Reverse Flash quickly regains his powers and almost kills Arrow, but Barry stops him. Flash then lures Reverse Flash to a nuclear blast from Firestorm. With Reverse Flash stunned, Arrow hits him with another nanite-powered Arrow. With his powers once again gone, the Reverse Flash falls and is finally defeated.
Before Arrow leaves, he ominously tells Flash that he may need his help soon. Flash agrees.
With the other heroes gone, Flash stands over his arch-enemy and revels in his victory.