“Think Fast” lives up to its name as things move quickly through the episode. Devoe has reached the final stage of his plan so a lot of things are coming together all at once. It’s up to Team Flash to think quicker, something they have not yet managed. They do get a little help this time though in the form of one Team Arrow member.
We see John Diggle showing up at an A.R.G.U.S. black ops site and once his credentials and DNA are verified, he orders the meta dampener on the building to be turned off. He’s about to head inside when some random pop song starts playing (not for sure where it’s coming from). Just in case you weren’t aware, this is not actually John. Devoe uses Killg%re’s powers to change the music to a symphony. He begins to kill security and soldier to the music, like a deadly conductor. Against humans, he’s basically invincible. He makes it all the way to Fallout and then sets him charging.
Harry is steadily declining and that’s especially evident when he says he’s found a blog that talks about The Thinker and everything they have been doing. This is, of course, Iris’s blog which she had asked him to proofread earlier in the day. Walking without running into things appears to be a challenge now, as well.
In an effort to find out what’s keeping her from being able to bring out Killer Frost, Caitlyn goes to see Dr. Finkle. While the doctor thinks Caitlyn has some repressed memories that may be causing her issues, Caitlyn disagrees.
Knowing that Devoe needs Fallout, the team has to talk with someone at A.R.G.U.S. to find out where he is. Luckily, they have someone on the inside. Barry heads off to grab John Diggle and the team prepares with trash cans and a bottle of water since John doesn’t take speed traveling well. Despite being made sick, he tells them where Fallout is, a place called The Castle. When he logs in to check the security of the building, it shows John was there and that Fallout has already gone critical, past being saved. Devoe plans to use him as a battery to power his satellites. They have twelve hours until Fallout reaches the power level needed.
Barry takes Diggle back and then prepares to storm The Castle. Unfortunately, being an A.R.G.U.S. facility it has incredible defenses, including randomized electrical plates. Barry believes that he could use the current from them to get fast enough to make it through Devoe’s pocket dimension. As usual, Devoe has thought of everything. While the electrical plates might make Barry fast enough, the resulting electrical explosion would kill anyone else. For this reason, Devoe has hostages that he’s keeping suspended over the electrical plates using Null’s powers.
On the homefront, Joe is doing everything he can to prepare for the impending birth of his baby. When Cecile tries to calm him down, she randomly starts talking like an eighties surfer dude and it’s super freaky. A moment later, the pizza guy shows up and he talks the exact same way. Obviously, Cecile has a new power that she’s not even aware of. Joe decides she needs to get checked out.
At the lab, Iris is still failing at finding Marlize, but Harry shares the wisdom he has learned – that if you want to understand someone’s action then you have to understand the feelings that motivate them. So, she needs to figure out where Marlize has been in her past that might make her feel safe.
Cisco and Caitlyn have come up with a plan for defeating Devoe and saving the hostages. The plan is that they join Barry in Flashtime. Barry is understandably skeptical since he can’t hold onto them the whole time he’s fighting Devow. They figured a way around that though. When Barry is in Flashtime, he’s actually generating speed force around him, like an aura. As long as he brings them into Flashtime with him, he could let go. They wouldn’t be able to last long, but it would be enough time to rescue the hostages while Barry takes on Devoe. So training begins.
And said training does not go well. Cisco still can’t breach when in Flashtime and try as he might, he ends up with his legs getting stuck when he loses focus and hits the floor.
Caitlyn checks Cecile over and says that the hormone relaxin, which causes the body to stretch to accommodate the baby and delivery, is also causing her powers to stretch. Instead of just being able to read minds, she can now inhabit them. (Wonder who that might come in handy with. Hmm…) Cecile freaks out and momentarily becomes Caitlyn, talking about Dr. Finkle and cleaning a beaker. A puff from an albuterol inhaler centers her again, but there is no long-term solution. She just has to deal with it until she gives birth.
Harry and Iris are starting an information board to find Marlize when Harry gets the idea to turn Marlize to their cause. She could be the key to everything. Iris points out that Marlize stabbed her with a katana so the only thing they’ll be doing when they find her is throwing her in the tunnel. She leaves to go home, telling Harry not to follow her.
Training begins again and Barry reminds Cisco and Caitlyn to stay calm. This time Cisco is able to open a breach, but Caitlyn’s cold gun won’t work, just like with Killer Frost’s powers before. The irritation causes what happened to Cisco to happen to her and she’s stuck. She falls from Flashtime and since she’s moving at Mach speed, she’s thrown into the wall. The hit causes a memory to come back to her, a memory where she had fallen off her bike and her leg was caught. It looked like while she was stuck, a truck may have hit her.
When Caitlyn wakes up, Barry once again states his reluctance in training and says it has to stop due to how dangerous it is for them. He flat out refuses to continue and says he’ll find another way to save the hostages.
Not listening to Iris, Harry shows up at her and Barry’s apartment to encourage her to put herself in Marlize’s shoes. What he manages to do is upset her more by tracking mud into her house. When Harry points out that it’s more of a loft, she states that she doesn’t care because it’s her home, the first place she and Barry owned together, and that it makes her feel loved and safe. That thought triggers her into finding the first place Devoe and Marlize lived.
At Joe and Cecile’s, Cecile has taken on Joe’s persona, getting everything ready for their run to the hospital. Albuterol doesn’t help. Instead, things get worse. She doesn’t recognize Joe anymore and insists that she is Joe. Through some calming words, he manages to pull Cecile back to herself.
Cisco and Barry end up in a huge argument revolving around Ralph’s death. Cisco says Barry can’t sideline him and Caitlyn because of what happened to Ralph and that there’s enough blame to go around for that. He also reminds Barry that he didn’t pull him from the speed force so he could say he’d save the world alone again. Finally starting to get it, Barry agrees to start training them again.
Iris tells Barry that they’ve found Marlize. He hands her one of the handy-dandy breaching buttons so she can go get her. Weird that he has no trouble sending his wife into danger, but tries to keep his friends from helping.
Barry, Cisco, and Caitlyn show up at the A.R.G.U.S. facility (I guess they decided that training was overrated) with the plan of Barry drawing the charge from the plates, Cisco laying the breach links, and Caitlyn protecting the A.R.G.U.S. agents with her new ice shooter.
With Fallout fully charged, Devoe shrinks his chamber down so he has a nice pocket-sized nuclear battery. Knowing Flash has arrived, he heads into his pocket dimension breach, but Team Flash is there and entering Flashtime. All goes according to their plan, as unlikely as that seems, and Barry shows up just as Devoe launches the satellites using his powers. Barry manages to launch the blast shard and destroy one of the satellites.
Devoe seems completely unphased by this and instead, explains that all he is doing is in an attempt to bring peace to the world, but Barry says he’s taking away free will. Devoe admits to that, but says it’s a price worth paying. Naturally, Barry disagrees and talks about how we’ll no longer know each other. Parents won’t remember their kids and husband won’t remember their wives. Devoe says emotion is a weakness that undoes progress and that love is the worst of all. For some reason, Barry doesn’t even try to stop him as he goes back to his pocket dimension.
Still at the A.R.G.U.S. facility with the saved hostages, Caitlyn decides that is the perfect time for Cisco to help her with that moment of memory she recalled. He’s not keen on the idea, but agrees to vibe her back to it. What she learns is that, even at that young age, she had turned into Killer Frost. The particle accelerator had nothing to do with her meta powers. It seems like her mom may have some explaining to do.
Harry and Iris show up at Marlize’s old apartment and find her with her electric katana. Harry tries to explain why they are there, but he can no longer easily verbalize ideas. Marlize is captivated by this. It was something she and Devoe had hypothesized about but had never seen. Iris uses this moment to point out that Devoe has gone too far and that he needs to be stopped. Marlize agrees, but says that he is right and has even proved his own point, that man will corrupt even the best ideas and intentions. Iris reminds Marlize of how she used to be, that she used to believe in humanity, and asks her what she would do to save the world.
Back at S.T.A.R. Labs, they learn that Devoe has used Killg%re’s powers to take over their own satellite to replace the one that exploded. Somehow, Devoe has let himself into their building and into the secret room where Gideon is. He uses her to start the Enlightenment. It begins.
The season finale is next week and it seems the world has fallen into chaos thanks to The Enlightenment. Marlize must have agreed to help because Barry uses the floaty chair she stole to enter Devoe’s mind. A battle of wills may be taking place. What will prevail, Barry’s will to save the world or Devoe’s will to control it?