This article contains spoilers for the Flash season four episode – Lose Yourself.
Last night's episode revolved around three main things, finding the last bus meta Edwin Gauss (Arturo Del Puerto), teaching Ralph (Hartley Sawyer) a lesson and having an intervention with Harry (Tom Cavanagh). Ralph and Barry (Grant Gustin) go to the bus where it all happened and discover an image of Gauss that makes it seem like he was there and not there in a blink of an eye. We also find out that Ralph is perfectly fine with killing DeVoe if need be. Barry tries to explain to him that there is always another way. They are called back to S.T.A.R. Labs where Harry has used his thinking cap to create what he calls the Sonic Scepter, a tuning fork that creates the same sound wave that could break through the Thinker's force field. He's also come up with a predictive algorithm to figure out where a breach from a pocket dimension will take place. Caitlin (Danielle Panabaker) has figured out that she can switch to Killer Frost using a shot of adrenaline. And when the alarm goes off about a breach, the team Vibe's there only to discover it's not the Thinker, but rather Gauss mailing some letters. He sees them, freaks out and folds back into the pocket dimension.
Now knowing Gauss' powers, Wells is able to narrow down the number of breaches to which ones were the Thinker and which were Gauss, figuring out a good area to search for him. He hangs out in a tent city and when the team finds him, they are attacked by the Samuroid. Flash takes him out and Caitlin, who was the only one injured, is already healing thanks to her frost powers. Gauss is willing to stay in the pipeline and Ralph goes to visit him after once again arguing with Barry about doing the same plan over and over and why the Thinker is always ahead of them because they aren't willing to do what needs to be done. While talking to Gauss, Ralph discovers that their new friend has been to the Thinker's lair and can take him there. So he grabs the Sonic Scepter and plans to go kill DeVoe, but Barry stops him with a superspeed punch. Meanwhile, Joe (Jesse L. Martin) confronts Harry about his overuse and possible addiction to the thinking cap.
Barry and Ralph talk and we learn that Ralph isn't scared to die, he's scared of what DeVoe might do to the rest of Team Flash, that it's the only family he's ever had outside of his mother and he won't let DeVoe hurt them. Barry tells him that if Ralph kills DeVoe, it will be the end of Hero Ralph and that his friends don't want that to happen. Joe takes the cap from Harry and Harry goes nuts, like a junkie not able to find his fix. Joe proved his point. Flash, Killer Frost and Vibe (Carlos Valdes) get Gauss to open a breach into the Thinker's lair, telling him to close it, wait 15 minutes, open it again and if they don't have the Thinker, close it and never open it again. They go through and use the Sonic Scepter, but it has no affect because they're attacking a hologram. At the moment they went through, The Thinker (Miranda MacDougall) and the Mechanic (Kim Engelbrecht) breached into S.T.A.R. Labs to get the other metas and leaving Flash and co trapped in the other dimension.
Ralph confronts DeVoe who is in Izzy's body, just outside the pipeline. But DeVoe uses Black Bison and Dwarfstar's powers to enlarge and bring to life the dinosaur skeleton to attack Ralph. While he is fighting that off, DeVoe drains and kills Melting Point, Null and takes over Gauss. Harry races to the secret room with Gideon in it and has her add more dark matter to his thinking cap, overloading it and knocking him out. Iris (Candice Patton) confronts the Mechanic and they fight. Ralph turns his hand into a replica of the tuning fork and uses it to take down DeVoe. Iris, allows the Mechanic to stab her with a sword in the shoulder so she could get close enough to send her and the chair back to the pocket dimension, freeing Flash and the others. When the Flash arrives, he finds that Ralph had captured, not killed DeVoe… except DeVoe had used Hazard's powers to keep the shackles from working. He then uses Null's powers to make Flash to heavy to run and then he takes over Ralph's body.
Vibe and Frost breach in, but vibe is in a weakened state. Barry vibes through the floor, comes around with the fork, but is blasted before he can use it. When Frost attacks, DeVoe stops her by reverting her back to Caitlin. DeVoe then leaves in Ralph's body. DeVoe now possesses the powers of 11 of the 12 bus metas, Ralph's body won't deteriorate like the others and he can shift into the true form of DeVoe (Neil Sandilands) and he says his plan still isn't finished. Team Flash has completely failed to save any of the metas, they've lost Ralph, DeVoe used Melting Points powers to take away Killer Frost, and Harry seems screwed up after the thinking cap overload… which also produced enough dark matter that DeVoe took to use as part of his plan.
For a season that was supposed to bring back the fun, this is an extremely down ending to an episode. And Barry spent all episode trying to teach Ralph not to kill, except had he killed DeVoe, it would at least be over and Ralph would still be Ralph, etc. We're drifting into the territory where only time-travel can undo the mess… and Barry isn't supposed to do that anymore.
At this point there is only one bus meta left that DeVoe has not killed and taken their powers… and that's Fallout (Ryan Alexander McDonald). Since his powers are so extreme and DeVoe already has the body he really wanted, I'm guessing that Fallout was created as a distraction for Team Flash or some other purpose than to become part of the Thinker's powers. But regardless, it looks like Barry and the others want to move him to safety and since they don't have Killer Frost to cool him down anymore, they bring in Citizen Cold (Wentworth Miller) from Earth-X. You have to love the way that even killing off the character of Captain Cold, the Arrowverse keeps finding more ways to bring Miller back.