The Flash (2014– )
8 user 10 critic

Cause and Effect 

Barry takes desperate measures to stop Savitar, while H.R. keeps pressuring Tracy Brand to set a trap for Savitar and Killer Frost has an interesting proposal.


David McWhirter


Greg Berlanti (developed by), Andrew Kreisberg (developed by) | 5 more credits »

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Episode cast overview:
Grant Gustin ... Barry Allen / The Flash / Savitar
Candice Patton ... Iris West
Danielle Panabaker ... Killer Frost
Carlos Valdes ... Cisco Ramon / Vibe
Keiynan Lonsdale ... Wally West / Kid Flash
Tom Cavanagh ... H.R. Wells
Jesse L. Martin ... Joe West
Tom Felton ... Julian Albert
Anne Dudek ... Tracy Brand
Danielle Nicolet ... Cecille Horton
Richard Zeman ... Lucius Coolidge / Heat Monger
Andre Tricoteux ... Savitar
Liam Hughes ... Young Barry
Sasha Rojen ... Young Iris
Ken Camroux-Taylor ... Judge Hankerson


Barry takes desperate measures to stop Savitar, while H.R. keeps pressuring Tracy Brand to set a trap for Savitar and Killer Frost has an interesting proposal.

Plot Summary | Add Synopsis

Plot Keywords:

kid flash character | See All (1) »


TV-PG | See all certifications »






Release Date:

9 May 2017 (USA) See more »

Company Credits

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Technical Specs


Sound Mix:




Aspect Ratio:

16:9 HD
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Did You Know?


Cisco speaks negatively about Hartley Rathaway, his former co-worker who later became the Pied Piper. However, in his last appearance, Rathaway's personality appeared to be significantly altered due to one of Barry's time-travel stunts. Rathaway provided critical assistance to Team Flash and appeared to be on good terms with Cisco. It's possible that the Flashpoint incident may have changed Rathaway's demeanor back to his arrogant self. See more »


Cisco describes his former co-worker Hartley Rathaway, aka the "Pied Piper", as being a "dick", but Rathaway's personality was changed to that of a friend and ally due to a timeline alteration in the episode "Flashback". See more »


Cisco Ramon: So when the Legends found that message in the Waverider from old you saying "Don't trust Barry Allen", it was talking about Savitar Barry Allen.
Cisco Ramon: It's all coming together... in the worst way.
See more »


References Star Trek: The Enemy Within (1966) See more »

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User Reviews

This is nice!
30 June 2017 | by tomwitneySee all my reviews

Well, let me be clear about the rating 9 that I have given to it may seem higher and it is but I have to give this because overall the episode is underrated enough. So clearly, you have to look at this from a different perspective and understand what this episode was about for me this episode explained a lot about Barry and why is he like what he is like. So let me tell you what to do grab some popcorn and a cola then enjoy the episode and most importantly take it lightly and eventually, you will follow.

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