Tonight's episode of "The Flash," told the tale of two speedsters -- The Flash and Zoom -- and how sharing a similar childhood tragedy turned these two men into the two very different people that they are. Tonight's episode also showed Cisco learning more about his powers and his fears of going the way of Reverb, to the dreaded dark side. Wally and Joe also got closer this week and Wells continued to search for his daughter Jesse. No matter how crazy and scientific these "Flash" episodes can get, family is always at the heart of them, and the same can be said for this week's episode. The episode culminated in a literal Flash "Versus Zoom" race, the outcome of which forced Barry to make a decision that will shape the future of this season in a huge way.
The episode opened with a flashback -- Zoom's flashback -- to when Hunter Zolomon (Teddy Sears) was just a small child. Hunter heard his mother and father fighting after his father had returned from war. The military uniform that his father was wearing is exactly the outfit that Jay Garrick wears, including the metal helmet with the wings. In a moment of rage, Hunter's father kills Hunter's mother, while forcing him to watch. This trauma, his father's outfit and helmet, all left an immovable imprint on Hunter, similar to the way Barry's (Grant Gustin) mother's death left an imprint on him. What's interesting about Hunter's backstory is that he didn't get adopted by a family like the Wests, he went into the foster care system. As Barry, Cisco (Carlos Valdes), and Caitlin (Danielle Panabaker) discovered later in the episode, Hunter's childhood trauma and experience in the foster system turned him into a serial killer. When Harry Wells (Tom Cavanagh), figured out that Jay was really the convicted criminal Hunter Zolomon, he showed the team the news footage from Earth-2 about Hunter's crimes and arrests. What Wells didn't know was that Hunter had been exposed to the particle accelerator, which made him a speedster. Hunter then took on the identity of Jay Garrick, a heroic speedster, to give Central City hope. Unfortunately that was just a charade, a ploy for Hunter to give the people hope, then to take it away by becoming Zoom.
This revelation inspired Barry to reopen the breaches and stop Zoom once and for all. Using Eobard's tachyon technology Barry was able to go four times faster than Zoom. While testing the equipment he even traveled multidimentionally -- presumably to Supergirl's world for the crossover episode -- although that wasn't fully explained. With the ability to outrun Zoom, Barry just needed a way to open the breaches. Enter Cisco -- if Cisco could tap into his powers, like Reverb (his Earth-2 doppleganger) then he could possibly open the breach back up. Convincing Cisco he could do it proved to be a challenge for Barry, because Cisco was afraid that if he used his Vibe powers like Reverb, that he would become like him. Cisco used the example of Anakin Skywalker in "Star Wars," "I have the midi-chlorians, I have the power, but I could become Vader." This was a powerful scene between Cisco and Barry, because it perfectly paralleled Zoom and The Flash. Barry beautifully reminded Cisco that he won't be left alone to deal with his powers, but that he has a team -- a family -- to protect him and keep him from going dark. This pep talk worked, and by using Reverb's goggles, Cisco was able to open a breach.
With the tachyon device attached to Barry and the breach open, Barry led Hunter/Zoom on a wild goose chase all over Central City. Joe West (Jesse L. Martin), Iris (Candice Patton), Cisco, Caitlin and Wells were all back at S.T.A.R. Labs ready to fight Zoom in case he came for them. Barry led Zoom to the Lab and slowed Zoom down by showing him images of his mother and father. These images trauma triggered Zoom, which made him dazed and confused. Barry was able to put a speedster boot on him to stop him, which worked for a hot second, until Zoom speedforce ripped it off of himself and disappeared. Barry tried to find Zoom and chase him down, but he was unable to. Thinking Zoom was gone, Barry, Iris and Joe West went home, only to find that Zoom had taken Wally (Keiynan Lonsdale).
The episode concluded with Barry deciding without hesitation to give Zoom his speed in exchange for Wally's life. Zoom brought Wally back from Earth-2 to S.T.A.R. Labs so that Wells could engineer a way to extract Barry's speed. While everyone was waiting for Wells to finish enhancing the device, this gave Team Flash time to ask Zoom questions about being Jay Garrick. Firstly, Zoom did not kill his own speed mirage, he killed a past version of himself. Secondly, he knew he had to get close to Barry Allen and he used his alter-ego hero identity, Jay Garrick, to do it. Thirdly, Zoom really is dying, and taking Barry's speedforce was the only way to cure him, or so he believed. Fourthly, when Barry asked Zoom who the man in the iron mask in his prison was, Zoom said Barry would never believe him if he told him. That confirms what Teddy Sears said earlier about the team not finding out the masked man's identity until the season finale. With the device finished and Wally safe, Barry ran on the cosmic treadmill to ramp up his speed. When he was ready, Zoom injected himself with Barry's speed and he glowed blue and red with speedforce energy. Zoom couldn't leave without hurting Barry though, and attempted to kill him. Only Caitlin was able to talk him down, by asking him that if he had any real feelings for her at all, if he would let Barry live. At this Zoom let Barry go, and then he grabbed Caitlin and sped off.
Next week's episode of "The Flash" -- titled "Back to Normal" -- deals with the aftermath of Zoom's attack. Barry no longer has any speed, Harry Wells is kidnapped, and Caitlin is held captive by Zoom back on Earth-2.
A meta-human with super strength named Griffin Grey (guest star Haig Sutherland) mistakes Harry for Earth-1 Harrison Wells and kidnaps him, demanding that Wells cure him from his current condition. Realizing another brilliant Wells could help track Griffin's location, Barry asks Jesse (guest star Violett Beane) to help. Meanwhile, Wally corners Joe (Jesse L. Martin) about The Flash.