Reviewed by Louis Rabinowitz.

The Flash has always had an interesting relationship with time travel. For a concept that’s intrinsically tied up with all sorts of laws and rules in most depictions, time travel in this show has been unusually deployed as more of a simple plot device than anything, with the mechanics, often a crucial part of time travel stories, relegated to a brief, cursory technobabble speech. Time travel has rarely made sense on this show, in short, but it’s certainly been utilised in memorable ways nonetheless. With that in mind, how did the latest episode fare, as it once again sent Barry back to the past?

Flash Back doesn’t come a whole lot closer towards providing a coherent and logical description of time travel, but it’s an episode that’s both intense and nostalgic in the ways it utilises time travel, nonetheless, while intriguingly expanding upon the mythology of time travel in this universe, even if it stumbles when trying to explore the consequences of Barry’s bull-in-a-china-shop routine back in the season one timeline. Having Barry travel back to a season one also gave us the opportunity to become re-acquainted with some characters who didn’t make it to season two – some appearances are more substantial than others, but there’s a lot of nostalgic fun to be had diving back into a simpler time; and Flash Back certainly takes advantage of this nostalgia with a cavalcade of references and nods to past events that seem a little quaint and far-off now. The Flash is a very different show now to that point in time, and Flash Back takes good advantage of the opportunity to gaze back at the show’s past while subtly comparing past and present circumstances.

The big idea that Flash Back added to The Flash’s version of time travel was the ‘time wraiths’, beings that hunt down speedsters messing about with the timeline. As with everything concerning time travel on this show, the wraiths are barely explained, with their oddly specific nature almost certainly suggesting that they’ve been cooked up to cause Barry trouble for this episode. And yet, they work as an idea because they add complexity to this show’s time travel on a very simple level – it’s The Flash’s (ahem) flashier, more ostentatious version of adding genuine consequences and pushback from the timeline after irresponsible actions, thus ensuring that time travel isn’t a free for all where everything can be changed with absolutely no fallout. Some might prefer a more logical and scientific version of this idea, but the time wraiths are a perfectly effective way of visually representing the idea that time travel is a process that has to be handled with care and precision, or else the timeline itself will fight back. As for how the time wraiths look – their design is fine, and relatively imposing (although as heavily lampshaded here, they do look like cheap Dementors), and there’s some pretty chilling visuals at the end when the wraith is sucking the life out of Barry, so their actual execution is solid enough. And yes, Flash Back does struggle to logically retrofit this idea by claiming they’ve always been around, but as villains for the episode that demonstrate the consequences of irresponsible time travel, they’re a good idea that can certainly be revisited in further time travel stories.

Undoubtedly, Flash Back was given a huge boost by the presence of a familiar face in the form of Eobard Thawne – it’s Thawne’s second appearance this season, but Flash Back served up the full-blooded, evil ‘Wells’ we knew and love rather than the less entertaining real Thawne. Tom Cavanagh has been a terrific performer on this show since the start and into season two, tackling the difficult challenge of playing two identical characters with ease. His skill in imbuing evidently different personalities and tics into two people who are, on the surface, relatively similar (in that they’re uber-clever and abrasive scientists) is apparent more than ever here when he’s tasked with playing the two versions of Wells in the same episode, with Cavanagh demonstrating a consummate level of versatility that’s unmatched by any other actor’s doppelganger performances as yet. His versatility is impressive, but it’s worth highlighting here how great it is to see Cavanagh slip back into the original, evil Wells, once again embodying the entertainingly cocky, hubristic madman with a devout, violent passion for accomplishing his mission.

It’s the confrontation between Thawne and Barry that marks Flash Back’s highpoint – a compelling, tense scene that effortlessly resumes the cat-and-mouse dynamic between two men that’s now on a far more level playing field than it ever was with season one, replicating the simple brilliance of season one’s hero/villain dynamic while adding a new spin on it that’s informed by Barry’s subsequent development. Eobard Thawne is a crucial character to The Flash’s mythos, and it’s great to see that the show is continuing to demonstrate the enduring importance of this dynamic to Barry’s character by somehow contriving appearances from Thawne even after he’s been erased from existence (a prime example of how a lot of The Flash’s great ideas concerning time travel make very little sense logically, but work wonders on a dramatic level).

Part of the fun here was the disastrous chain reaction of events spiralling out of Barry’s control as his plan for the past rapidly falls apart. It’s rooted in questionable behaviour, which means that a lot of Flash Back relies on Barry being a little bit dim (this would be more of a problem if many other, great Flash episodes didn’t rely on the same thing), but the way Flash Back knocked down the dominoes of Barry’s plan throughout the episode was provided the sense of tension and escalating stakes that it needed, with a legitimate sense of unpredictability pervading about the degree to which the timeline would be messed up by Barry’s actions. There are a lot of effective moments where a spanner is thrown into the works for Barry such as the impromptu reappearance of his older self (which leads to some fun visuals of the two Flashes working together with their red and white emblems) – though it’s based on dumb behaviour, it’s undoubtedly entertaining usage of time travel to create tension and excitement while providing memorable visuals along the way. Flash Back builds consistently to the climax as more dominoes topple and Barry’s plan goes even more awry, so it’s a bit of a shame that it’s inhibited by the fact that it doesn’t quite provide the satisfying pay-off to reward all the great build-up.

Barry makes some pretty big waves in his time in the past, even revealing himself to everyone in STAR Labs (including his past self) and dumping a whole lot of information about their future on Thawne… only for almost nothing to have changed. The trick with Rathaway is fun, but the promised consequences of Barry’s actions once he returns feel minimal and cursory – for the most part, it feels as if nothing has changed despite these huge alterations to the timeline. The only real change is the Pied Piper’s return to the side of good – while it’s a very effective ‘what?’ moment to see Rathaway helping Team Flash out, he’s still just a guest villain who appeared in two episodes once, so his transformation doesn’t have that much weight. With just a few more small nods to changing circumstances other than Rathaway’s change to the side of the angels, Flash Back could have sold the idea that this was a broadly similar timeline where some details had changed, but there’s no evidence of that as the episode seems to just pick up in the present from where it left off before Barry’s travel back. It undercuts some of what could have been a truly excellent episode, removing credence from the central idea that time travel has consequences – it’s not technically a cheat because it does adhere to what we know, but it certainly feels like The Flash circumvented some really interesting ideas here in favour of a shortcut back to familiar waters. It’s not a crippling flaw, but it’s a frustrating one for sure.

Though it’s an episode tied up in cerebral time travel fun, Flash Back still remembers the heart that makes The Flash what it is, cleverly utilising Barry’s trip back for a great emotional kick to close out the episode. Eddie’s re-appearance first seems like a fun but dispensable way to get Rick Cosnett back when the opportunity was there, but his message to Iris is a genuinely touching and affecting moment that’s tinged with nostalgia, but also distinctly forward-looking in how it gives Iris the closure she needs to strive forward with her own relationships free from his memory. Rick Cosnett puts every ounce of likeable pathos into this small speech – so while it’s a bit too self-conscious of its status as a crucial closing speech for something that’s meant to be a quick, rushed birthday message, it still strikes all the emotional notes needed because of Cosnett’s heartfelt, genuine performance.

So, now Barry has the tools for speed upgrade he needs to fight Zoom, and the trailer for next episode shows that we’re getting not only the next Barry vs. Zoom face-off then, but also a huge amount of back-story on the complicated origins of Zoom. Next week should be fun, right? Hang on… the next episode is on April 19.

Thanks, CW!

Rating: 8.5/10

For an episode so focused on underlining the consequences of time travel, Flash Back skimps on consequences when it’s most necessary, but it’s still a very good, inventive instalment that takes a nostalgic trip back to season one for an hour of television that’s enjoyably intense yet deeply silly fun.