"Flash Back" is the seventeenth episode of the second season of The Flash. It aired on March 29, 2016.

Episode Synopsis

After the shocking revelation of Zoom's real identity, Barry is more determined than ever to get back to Earth-2 to stop Zoom forever. Desperate to find a way to increase his speed, Barry decides to travel back in time and masquerade as his earlier self in order to get his arch-nemesis,Eobard Thawne, to teach him how to run faster. However, things do not go as planned and Barry is stunned to face familiar foe Hartley Rathaway, as well as old friend Eddie Thawne. Iris makes peace with her past in order to embrace her future.


Barry talks with his adoptive family at the West house and Wally makes a wishful comment about how he wished some great engineers and mechanics were still around to teach him firsthand. This immediately inspires Barry, who believes that if he runs back into the past, to about a year ago, he can get Eobard Thawne (disguised as Wells) to help him get faster. 'The Man in Yellow' was the only one able to crack the equation and manipulate the Speed Force. He convinces Cisco Ramon and Caitlin Snow to help him, much to their dismay. Cisco warns him of tampering with the timeline- if too many things are changed then reality could collapse or Barry could get stuck in an eternal time loop. Caitlin gives Barry a drug to knock out his past self with so he can switch places with him and get Thawne to help him with the speed equation. He travels through the Speed Force and sees scenes from past events in his life and a strange looking creature- which is later revealed to be a time wraith.

Once Barry arrives in 2015 Central City, he realizes that he arrived too early. Paralleling season one episode 11, The Sound and the FuryBarry see's himself outside battling Hartley Rathaway, aka "Pied Piper." Deciding to just take his early arrival in stride, Barry manages to speed his younger self away, and after a brief tussle, manages to stab him with the knock out drug and switch their emblems. He then returns to take Rathaway back to S.T.A.R. Labs and lock him into the pipeline. Remembering that the villain had used his enhanced earpieces to blow the door off the cell holding him, Barry tells Cisco to scan for any low EMP pulses, resulting in taking his earpieces away from him before he can do any damage.

Back upstairs, Barry asks Thawne if he can help him get faster, suggesting that they've been going about his training all wrong. He tells him that he isn't the fastest man alive and the Man in the Yellow Suit is still out there, and to beat him he has to get fatser himself. He draws up a speed equation, which impressions Thawne but also surprises him. Before he can really help Barry though, an ding from the computer alerts them to an attack at the CCPD. Barry reluctantly goes to see what the danger is, but by the time he gets there the crisis has passed. A time wraith had recently attacked the police force and broken into Barry's lab- most likely the same one he saw when he was traveling back in time at the beginning of the episode.

He returns back to S.T.A.R. Labs and tells the team what happened. They are all puzzled, and Barry mentions that he'd seen the creature before- but quickly backtracks before he mentions it was in the Speed Force. Instead, he lies and said he saw it when he was battling Hartley Rathaway (which isn't completely untrue, since he was traveling through time while his younger self battled Pied Piper). Thawne, growing more suspicious with each passing minute takes Barry aside into a room without Caitlin and Cisco and knocks him out from behind.

When Barry awakes, his wrist has been handcuffed to Thawne's wheelchair and the two speedsters are in the Reverse- Flash's time vault. Thawne proceeds to interrogate Barry about who he really is and what he's doing. It manages to come out that Barry is from the future and the time wraith is angered at him tampering with the timeline too often. The reason it didn't go after Thawne is because he covered his tracks and knew what he was doing, whilst Barry was inexperienced at it. Barry attempts to play innocent but after a) revealing he can vibrate his hand (which Thawne hadn't shown younger Barry yet) and b) Thawne speeding around the room without Barry flinching at all, it's pointless. Thawne threatens to kill the scarlet speedster but Barry merely tells him that he wrote his younger self a letter that described in detail how he defeated the Reverse Flash, so killing him wouldn't be in either of their favor. Thawne finally agrees to help him, tricked into thinking that he finally got to return home in the future instead of being erased from existence. Harrison is basically blackmailed into helping 'future' Barry, else his plans be ruined.

Meanwhile, Cisco down at the pipeline asks Hartley how his gauntlets work while blasting Never Gonna Give You Up by Rick Astley. Hartley agrees to tell him if he'll cut the music. Cisco also gives Hartley nonexplosive earpieces to help with his hearing condition. Upstairs in the cortex, Caitlin is attacked by a time wraith, but she manages to escape down to the pipeline where Cisco and Hartley are. They lock themselves into Hartley's cell, hoping the wraith wouldn't be able to get in. They call for Barry and Wells to help, but the two are otherwise occupied in the time vault. Hartley takes matters into his own gauntlets and sets the frequency to one that is painful for the wraith, which makes it eventually retreat because of the pain. He was able to do this because he rigged them to S.T.A.R. Labs speakers so he'd be able to emit a destructive frequency if the gauntlets were disarmed.

Caitlin is able to deduce, once the team has assembled back upstairs, that the two places attacked were the CCPD and S.T.A.R. Labs- the link being Barry. Wells tells Cisco and Caitlin to repair Hartley's gauntlets, seeing as that was the only way to hold it off. Wells admits to Barry he doesn't know how to stop a time wraith because no one ever has. He goes on to explain that yes Barry time traveled before and never saw a time wraith because they were being lenient. Now, he's run out of luck and the wraith won't stop pursuing him until he's dead. 

Barry heads to CCPD once again, to see if he can get anymore clues on how to stop the Time Wraith. He finds that it didn't leave any trace elements or prints- practically a ghost except the mess it left behind. Eddie enters the room while he's scanning and Barry asks him to say a few words for Iris' birthday while he records it, claiming he's making her a birthday montage. "Just speak from the heart. Talk as if it was the last thing you could ever say to her."

At S.T.A.R. Labs, Wells and Cisco are working on the gauntlets but the electron guns have been fried, which in turn destroyed the amplifiers. The team agrees that they need Hartley to help them but just then past Barry (at this time, present Barry from 2014) races into the lab demanding to know where the other Flash is. Cisco and Caitlin are confused, but Barry from 2016 walks into the lab. Cisco assumes that one of them is a doppelgänger to which present Barry replies "no, not yet." They confuse Cisco more when they can both recall watching "Wrath of Khan" with him. Eventually, after a lot of confusion, 2016 Barry is able to explain to them that he is from the future and a time wraith is chasing him. 

2016 Barry and Wells go back down to his time vault where Wells gives him a flash drive with the answers to his speed equation, which would be tachyon enhancement. Wells hopes that if they can return Barry back to his timeline without causing more damage, the wraith will stop attacking. 

Once they get back to the cortex, Cisco has managed to find the wraith via satellite and reports that it's coming back. 2014 Barry insists that 2016 Barry needs to leave. 2016 Barry tells Cisco that they have a year to figure out how to stop the Time Wraith for when he returns back to his normal timeline. He also pulls Cisco aside and tells him that Hartley knows where Ronnie is, getting Team Flash back on track with their regular timeline. He and 2014 Barry switch their respective emblems back.

Down near the particle accelerator, 2016 Barry runs around it to build up speed while the Time Wraith pursues, slowing him down at the same time as he tries to open a portal back to his time. 2014 Barry goes down to help, by kicking the Time Wraith away from his future self- allowing 2016 Barry to speed forward and get back to his own time stream, the Time Wraith following close behind.

He's thrown back into S.T.A.R. Labs and Caitlin and Cisco try to shoot the wraith with a weapon they've created. However, it doesn't work and it attacks Barry, its touch aging him within a matter of seconds. Hartley Rathaway appears at the last second and blasts the wraith with what appears to be new improved gauntlets. It evaporates before their eyes, leaving Barry confused as to why Hartley is in S.T.A.R. Labs. He goes as far as to ask how Barry's trip was, before going off to dinner with his parents.

The trio head down to the time vault to go through the flash drive Wells gave him, but it doesn't work. Out of frustration, Barry hits the stand it's plugged into and the contents float up on the holographic screen. 

Barry and Wells have a heart felt moment upstairs about Jesse, who Wells is still trying to find after she left in the last episode. He talks about how he only enjoyed science, but the moment Jesse was born all he wanted was her love. Barry comforts him and says that he has to trust that in the long run he's made the right decisions.

Barry heads back to the West house where Iris is sitting on the couch, flipping through a photo album of her and Eddie. He mentions that he was going through some files on his phone and found a clip by Eddie when he was creating a birthday video montage for her. She watches the video of Eddie and based off her reaction, she is finally able to move on.

Barry ends the episode saying that sometimes the only way to move forward is to revisit the things in your past that were holding you back. He goes back to S.T.A.R. Labs, picks up Jay's old helmet and stares at it ominously before saying, "I'm coming for you."


  • The time wraith bears a remarkable resemblance to the comic book "Black Flash." However, it is believed that in order to avoid confusion with the speedster already wearing a black suit, the Black Flash was renamed to 'Time Wraith.'

Episode Gallery

Episode Promo

The Flash 2x17 Extended Promo "Flash Back" (HD)00:48

The Flash 2x17 Extended Promo "Flash Back" (HD)

Episode Images

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