The Flash - 'Flash Back'

"You want to do what now?"

Unable to crack the vital speed equation which will allow him to run faster (and, I note, ignoring the implications of Caitlin's research that his running technique might need work,) Barry is inspired by a chance comment from Wally to seek help from the one person who does know how to enhance the speed force without soul-destroying, body-dissolving drugs: Eobard Thawne; not by reading his journals or quizzing Gideon, but by travelling back in time and pretending to be himself for long enough to get the solution to the equation.

To quote Harry Wells, for all his flaws fast becoming my favourite character: "Your plan is asinine."

Still, when has Barry ever let a little thing like common sense, contrary advice or the blatant and repeated evidence of his own shortcomings as a strategic thinker get in his way? Caitlin whips up a dose of six hour Flash-tranquiliser and off he runs to the time when the team were fighting Hartley 'Pied Piper' Rathaway.

It's that man again.

Things go wrong from the off, as a hideous 'Zombie Flash' appears and throws him out of the Speed Force too early in the episode. Barry then has a punch up with his younger self before delivering the knock out draft and then taking down Rathaway himself. Committed to not altering the timeline, he doesn't warn Cisco and Caitlin of Rathaway's explosive cochlear implants... oh wait, he does exactly that, and then proceeds to oh-so casually drop a near-complete speed equation into a conversation with 'Wells'.

And then Zombie Flash pops out of Barry's crime board at the CCPD, calling Barry away from his discussion and bringing him face to face with Eddie Thawne. On returning to his conversation, Wells knocks Barry out and quizzes him about the future, since he knows that the Zombie Flash is a Time Wraith, a peril of time travel which Barry is too inexperienced to avoid. Wells suggests that they protect the web of time, although from its actions it seems more like they just go crazy over the scent of time travelling speedster.

This is not good.

Hartley manages to overload his gloves and drive off a Wraith attack with a sound burst, but then younger Barry shows up and in total fairness the scene is priceless. Caitlin denies mixing a Micky Finn to knock out pastBarry, while Cisco goes into a metaphysical fugue over whether the idea for the revised Flash logo was original or self-creating now that he's seen it before devising it.

Thawne gives Barry the secret of tachyon enhancement on a flash drive for the time vault's computer system and sends him home with the Wraith in hot pursuit, leaving Cisco and Caitlin a year to work out how to stop it. Having screwed up that part of the timeline, he also tells Cisco that Hartley knows where Ronnie is, returning to find Hartley himself waiting to zap the Wraith, whatever changed having made him a decent guy and honorary science bro.

Barry also brings back a recording he made and claims to have 'found' of Eddie explaining just what he feels for Iris, to help her move on with her life.

'Flash Back' is a decent episode, but brings up once more Barry's near-total inability to stick to simple, common sense rules. "Don't get involved with your doppelganger," Harry warns in 'Welcome to Earth-2'. Does kidnapping yourself, making out with your alternate's wife and getting his father in law killed count as 'involved'? Here, he can't resist shoving his oar in when Hartley is captured, potentially scotching the recovery and stabilisation of Firestorm, and the fact that so few things go wrong as a result of his actions is a miracle. And what is it with him and abducting his alternate selves?

Overall then, this is a fun glimpse back at what was, with some added character notes for Iris in particular. Tom Cavanagh also gets to revert to his former role for a while, once more expertly mixing his pride in his team with his ultimate and overriding goal of regaining his full connection to the Speed Force and getting home. While it has fun with time travel, by introducing the Time Wraith, the episode is clearly looking to ensure that Barry doesn't get to confident, leaving that sort of thing to Legends of Tomorrow.