“Fast Enough” is episode twenty-three of season one of The Flash and the season finale.
In the previous episode, “Rogue Air”, the attempt to transport the meta-humans across town so they would be taken in a plane to Oliver Queen’s secret military facility did not go well. Basically because Snart double-crossed them; he pointed out to Barry that he is, after all, a criminal. Barry’s battle, with the aid of Arrow and Firestorm, with the Reverse-Flash appeared to go rather better, with Eobard Thawne – it doesn’t seem accurate to really call him Harrison Wells – knocked down by one of Oliver’s arrows, one which looks to have disabled his speed.
The episode begins with Barry narrating, just as he has always done before, but this time in a different tone of voice and, instead of the usual intro with clips of Barry saving people, the others, including Ronnie and Dr Stein, are at S.T.A.R. Labs. Barry concludes, as normal, with him saying that one day he will find who killed his mother and get justice for his father. Only he continues, saying that day is today, as Barry stands in front of an imprisoned Eobard Thawne.
Thawne makes a comment about no Big Belly Burger – he says that’s one advantage of the past, as there are no cows where he comes from. Barry asks when that was and Thawne tells him that he was born 136 years from now – but says that’s not the real question that Barry wants to ask. So Barry asks the question – why did Thawne kill his mother. Eobard’s response is because he hates Barry; not the Barry of now, but the one years from now. Not necessarily in the future, but a future.
Thawne and Barry were rivals, enemies, opposites; the reason why doesn’t matter anymore. What matters is that neither was strong enough to beat the other, until Eobard learned Barry’s secret – his name. So he travelled back in time, to kill Barry Allen as a child. Barry, the future Barry, followed and they fought. Future Barry got young Barry out of there and Thawne was so angry, he thought what if he made Barry suffer a tragedy, so that he never became the Flash. So Eobard killed Barry’s mother. Finally, Eobard could return to a future without the Flash. Only by travelling back in time, Eobard had lost his way home, and he lost his ability to harness the Speed Force, so he was stuck in the past.
Thawne’s only way back to the future was, ironically, the Flash. So he created the Flash again. Thawne needed Barry to go fast enough to rupture the space time barrier and create a stable wormhole so that Eobard could return to his own time. Barry wants to know why he would do this. Thawne tells him that, if Barry gives him what he wants, he will give Barry what Barry wants – to save his mother and prevent his father from going to prison. Unsurprisingly, Barry is rather angry about this and Thawne tells him that he knows that rage, as he used to feel it every time he looked at Barry. Now, Thawne claims, he knows what Joe and Henry feel when they look at him – love and pride. Thawne claims they have a chance to undo all that they’ve done.
So Barry goes to speak to the others. Caitlin says that it’s cut and dried; if there’s a chance to save a loved, it should be done. Dr Stein tells her it’s not that simple, as it comes with unparalleled risk. When Future Barry saved young Barry, he altered the timeline. When Joe mentions that was only one day, Stein agrees – and says imagine what 15 years of such changes would be like. Nothing would be the same and they have no way of knowing what Barry’s lie would be like. Joe’s answer is simple – Barry has to change the past. When Barry goes and speaks to his father, Henry’s answer is equally simple – he shouldn’t do it.
Barry does decide to do it, and Thawne explains how. When the particle accelerator is fired up, only one particle will be injected into it, not two. Barry will have to run fast enough and collide with the particle. If he doesn’t, he will die. The calculations show that Barry will need to reach Mach 2. Joe asks what would happen if Barry isn’t running fast enough, as he’s getting an impression that it would be like a bug hitting a windshield. Which is apparently a pretty accurate analogy. There’s also another risk of doing it, a really big danger that would be really, really bad.
Eddie is feeling rather down thanks to Thawne showing him the paper from the future that showed Iris had married Barry. Dr Stein talks to him about it and essentially says so what? That doesn’t mean it will happen. This has a big effect on Eddie, especially as Stein tells him how important he is. Cisco has a talk with Thawne, and Thawne tells him something that, if true, is a bit of a shock to Cisco.
Things don’t quite go the way planned and the episode ends on a cliff-hanger leading into season two and “The Man Who Saved Central City”.