Exploring the consequences of Flashpoint, The Flash Season 3 has dealt Barry some interesting curveballs — and the biggest twist of all was in the mid-season finale, when Savitar prophesied death, betrayal, and suffering for all of Team Flash. Running a few months into the future, Barry witnessed Savitar brutally murdering Iris, though it's still unsure whether Barry the team can change this course of events, and who will die if they do.
But that's not the only mystery The Flash Season 3.5 poses. Recently, two characters from Season 1 have been announced to return after the hiatus: Ronnie Raymond (Caitlin's husband and half of Firestorm), and Eddie Thawne (Iris' fiance and partner of Joe West).
As with many returning guest stars, this announcement isn't just news to fans, it's also a crucial hint about the plot of Season 3.5. In superhero stories, few characters are ever really dead, so it might be that Ronnie and Eddie have been resurrected in some way. But knowing #TheFlash, it seems far more likely that the return of these characters is due to some time travel or alternate dimension plot.
Considering both characters were staples in Season 1, it's possible that a few episodes will concern Barry running back in time and encountering his old allies. Yet, after many episodes examining the consequences of time travel — and with a whole other #Arrowverse show all about time travel — we're leaning heavily towards the other option.
A Multiverse Of Possibilities
In Season 2, The Flash opened up this DC continuity to the concept of the multiverse, exploring strange new worlds through the course of the season, as Zoom embarked on his reign of terror.
"Welcome To Earth-2" and "Escape From Earth-2" were some of the best episodes in the entire show, as they offered us a view of a totally different world to the one we know and love — with some eerie similarities. Unfortunately, Earth-2 is the only alternate universe we've had a close look at, despite that brief glimpse of Jay Garrick's Earth-3 in Season 3. With the fascinating plot prospects posed by the multiverse, many fans have been eagerly awaiting the chance to see more from the other Earths out there — and these returning case announcements may mean we're going to get just that.
Ronnie seems to be the most likely to be visiting from another Earth, thanks to Caitlin's intriguing Killer Frost plot in Season 3. As she develops her cold powers, Caitlin has been growing increasingly worried that she'll become the villainous Killer Frost, whom she met during her visit to Earth-2. Killer Frost didn't work alone, though: She was accompanied by an evil version of Ronnie Raymond, called Deathstorm, who later died at the hands of Zoom.
Or did he? As Firestorm/Deathstorm, Ronnie has extraordinary healing capabilities, and it's entirely possible he survived Zoom's attack. If she encountered this version of Ronnie in Season 3, you can be sure Caitlin would be sent spiraling into yet more emotional turmoil.
But Earth-2 isn't the only Earth out there, and we may already know where in the multiverse these doppelgangers originate from.
Welcome To Earth-19
Over a month ago, set leaks from The Flash Season 3 teased the arrival of another version of The Flash.
Thanks to his distinctive costume, fans soon identified this version of the Scarlet Speedster as the one from Earth-19, featured in DC's Elseworlds comics. This Earth also just happens to be the one Season 3's Harrison Wells hails from, so it would make sense that Team Flash would eventually venture over there.
With Earth-19's industrial revolution and classic noir setting, this promises to be a very exciting plot indeed — especially if the characters discover doppelgangers of both Ronnie Raymond and Eddie Thawne.
Of course, Season 3.5 has about 15 episodes to play with (the show was renewed for a 24 episode season, and we only reached Episode 9 before the hiatus), so it's entirely possible that the returning characters appear in a different episode to the one in which the gang travel to Earth-19. However, it does seem like Season 3.5 will deal with both time travel and alternate Earths, so all bets are off as to where, or when, these characters come from.
With a whole multiverse of possibilities out there, personally I'm hoping to see more alternate Earths — because let's face it, Barry should probably stop messing with the timeline.