'The Flash' Returns to the Show's Golden Age With "Cause and XS"

Long before Legends of Tomorrow made time travel casual in the Arrowverse, The Flash sporadically dabbled with some of the series’ best stories. Some of those episodes remain the best this multiverse has ever managed. And The Flash just delivered on one of its best entries in that categor yet.

Like the excellent “Enter Flashtime” from about the same point this time last season, Season 5’s “Cause and XS” explores time travel in a novel way by making Nora front-and-center while sidelining Barry.

Only on The Flash are the filler episodes some of the absolute best.

Full spoilers follow for The Flash Season 5, Episode 14: “Cause and XS.”

“Cause and Effect” might as well have been called “Deja Vu” because of how many times Cisco says he’s having deja vu in this episode. After discovering the final step of the meta-human cure, he spends most of the episode on a date with the bartender/photographer he met last week.

The Flash Cause and XS
In the original timeline, Nora confronts Cicada with Killer Frost after Iris is kidnapped.

Except, while Barry goes into the Speed Force to accelerate the meta-human cure by using tachyons as a catalyst, Cicada kidnaps Iris. Caitlin winds up dead. So Nora goes back in time to prevent it. She goes back again and again, and each time someone different from Team Flash dies, sometimes even Cecille.

Nora has learned a lot this season from working with Team Flash, but she makes it readily apparent in “Cause and XS” that she still acts a bit childish and can’t keep her cool in dire circumstances.

Only on the 53rd try does she get it right by reversing time on a smaller scale to move Cicada into the trajectory of his own dagger, wounding him on his left shoulder.

Along the way, Cisco gradually Vibes more and more of the alternate timelines in a way that’s deeply reminiscent of Season 1 when he half-remembered being killed by Eobard Thawne. It’s a nice callback that’s totally relevant here.

In the end, when Barry returns, he offers Nora a really interesting metaphor using a coffee cup as the space-time continuum. Every time they travel back in time, it fractures space-time as a whole. Even when it’s repaired, there’s still a fracture and things won’t be the same.

Barry had a traumatic time with Flashpoint, but his daughter’s more holistic approach to time travel claims that the timeline is malleable. Who’s right here? And what will it mean for the rest of this season?

The Flash airs Tuesday nights on The CW at 8 p.m. Eastern.

Media via The CW