Season 2, Episode 1: “The Man Who Saved Central City”
The second season premiere picks up where the first season finale left off, with Firestorm sacrificing his life to stop the singularity threatening Central City. Perhaps more importantly, it’s the episode where Henry, Barry’s father, is released from his wrongful imprisonment. The episode also introduces Jay Garrick, who plays a major part in the season as a whole.
Season 2, Episode 6: “Enter Zoom”
The Zoom storyline may have been riddled with plot holes and may have been more disappointing than not in its conclusion, but his first interaction with Flash was one of the best introductions of a villain in superhero television history. By the end of the season, he was as pathetic as he was threatening, but when he broke Barry’s back and dragged him through the city to show people that their hero wouldn’t be able to save them? He was absolutely terrifying.
Season 2, Episode 9: “Running to Stand Still”
I’ll be honest; the first half of the second season had a lot of episodes that accomplished very little. However, in a binge watch, it’s definitely necessary to see the introduction of Wally West, Iris’s long-lost, unknown brother. The plotline with Francine West was problematic at best. But the relationship between Flash, Iris, and Kid Flash is one of the most important in the comics, and so it’s definitely worth seeing the introduction of this beloved character in the series.
Season 2, Episode 12: “Fast Lane”
The inclusion of this episode on the list is perhaps arguable, as it may not be necessary to see how easily and quickly the team figures out how to close the breaches around the city (that were used to kill time while setting up the Legends of Tomorrow spinoff) if one hasn’t spent the past 11 episodes seeing them struggle to do just that. Still, it helps set up the plotline with Jesse, who’s been kidnapped and is being held hostage by Zoom, so it’s worth watching.
Season 2, Episode 13: “Welcome to Earth-2”
After a dreary – and trudging – first half of the season, this episode finally put the season on the right track, as Barry, Cisco, and Harry travel to Earth-2. The episode also featured some of the best doppelgangers on the show, with Earth-2 Barry and Iris being obvious stand-outs. While these particular doppelgangers would (sadly) not be featured again in the series, it’s an important episode, as the concept of alternate-world versions of our favorite characters would come into play again in the future. The following episode, “Escape from Earth-2” may not be as necessary to binge, but it does complete the two-parter and is thus well worth watching.
Season 2, Episode 15: “King Shark”
You can watch this episode to finally learn Zoom’s secret identity. And because it has a talking shark. Or you can take my word for it: “Jay Garrick” (as we know him to date) is Zoom. No, it doesn’t make sense. But you’re just going to have to roll with this one. If you want to learn Zoom’s backstory (he’s actually Hunter Zolomon, and his past is tragic), you can watch episode 18, “Versus Zoom” that establishes it. However, as this plot line has several plot holes, it isn’t all that necessary.
Season 2, Episode 21: “The Runaway Dinosaur”
An absolutely beautiful episode, directed by none other than Kevin Smith. While it does help move the plot forward in a few ways (once again hinting at Iris as Barry’s lightning rod when she pulls him out of the speed force, and Zoom assembles an army of metahumans to attack the city), the episode is bingeworthy mostly for the heart it brings back to the series. If you can watch the scene with Barry and the speed force projection of his mother as they read and recite the children’s book Nora read him when he was younger and not cry? You. Have. No. Heart.
Season 2, Episode 22: “Invincible”
In order to understand and sympathize with Barry’s decisions in the season finale, it’s important to see what pushes him over the edge. And that happens with Henry’s death in this episode, when Zoom tortures Barry by killing his father in a similar manner to the way his mother was murdered years before. Barry’s carried a lot of grief in his life, but can anyone really blame him if this loss is one too many?
Season 2, Episode 23: “The Race of His Life”
Wrapping up the season storyline, it’s Flash versus Zoom in this episode. However, perhaps more importantly, this is the episode when Barry, broken by his most recent loss, reconsiders his decision of the year before and travels back into the past to save his mother. It is a decision that would have some devastating consequences – for him and for others.