This article contains spoilers for The Flash season four episode 'Subject 9'.
With the series returning from Olympic hiatus, we pick up with Barry (Grant Gustin) newly out of prison and heading back to work, where Captain Singh (Patrick Sabongui) tells him that he is on indefinite leave. It seems some people, including the new Mayor, don't think he should be on the force anymore, even though Clifford DeVoe (Neil Sandilands) showed up alive in court.
With his newfound free time, Barry pushes harder to find the remaining bus metas. After having witnessed DeVoe kill Kilg%re, Dwarfstar, and Black Bison then discard Brainstorm's body in favor of Hazard's, he doesn't want DeVoe to kill anyone else. Ralph (Hartley Sawyer) checks the bus's lost and found to discover a CD by Izzy Bowin (Miranda MacDougall), who turns out to be a rising country western singer/musician who has the power to manipulate sound waves using her fiddle.
Ralph and Barry try to convince her that she's in danger, but she doesn't buy it and knocks them down with a sound blast then disappears. After everyone fails to track her using science, Ralph asks if they checked her social media, and they discover where she is. This time Flash, Elongated Man and Vibe go, but DeVoe (Sugar Lyn Beard) confronts them, pointing out that she now has six powers and uses just two to take out all three heroes. But Izzy uses a sound blast to hurt DeVoe, and the Mechanic (Kim Engelbrecht) appears and pulls her out. Izzy goes with Team Flash, where she makes a connection with Ralph and starts training her powers. But Barry pushes too hard and she bolts.
Meanwhile, Harry (Tom Cavanagh) tries to make friends with Cecile (Danielle Nicolet), who is having problems sleeping because of her new psychic abilities. After making a ridiculously large helmet, he reduces the size and they figure out that if he reversed the polarity (Doctor Who reference, anyone?) the device could keep DeVoe from transferring his consciousness to a new body. He names it the cerebral inhibitor — the same name Savitar has said last season.
Vibe locates Izzy, who is trying to call out DeVoe. Flash and Elongated Man race there and get the device on her, but DeVoe uses Kilg%re's powers to deactivate it and then puts up the force fields he used to trap Flash a while back. He then transfers into Izzy's body. Ralph is extremely upset, having gotten very close to Izzy, so DeVoe teases him by hinting that he would be using Izzy's body to be spending a lot of time with Marlize over the weekend.
Barry goes to Ralph, who vows to help find the other bus metas and bring down DeVoe. Ralph then gives Barry a business card saying he's a private detective working with Ralph. Trying to help Barry past the feeling of losing his identity with his job.
Of the nine bus metas they've found so far, six of them are now part of DeVoe and are basically dead. The Weeper is in DeVoe's possession and he's using his tears to control Marlize. Fallout is with Tina McGee and Ralph is with Team Flash. That leaves three left to find in nine episode… though I don't think we'll get one next week. DeVoe seems to be getting more an more impatient and rash as he switches… perhaps his master plan is to go through all of the metas, collecting their powers, and then end up in Ralph's body, where he can take any shape — including that of his original body.
As emotional as this episode was at the end, next week's may be the most intense episode of the season as Barry races against time — literally. A nuclear bomb goes off in Central City. While moving at super speed, he tries to figure out how to save the city — but if he stops running, it's over, and everyone dies. This is the episode, 'Enter Flashtime', that features the return of Violett Beane as Jesse Quick and John Wesley Shipp as Jay Garrick. And it looks like the one who sets off the bomb is Veronica Dale, aka Hyrax, an eco-terrorist who tried to do something similar in the comics that ended up taking the life of her lover… Green Arrow.