‘The Flash’ Season 3: How Kevin Smith’s Episode Could Set Up ‘Arrow’, ‘Supergirl’, ‘Legends’ Crossover Event

Just a few weeks ago,Executive Producer Greg Berlanti confirmed the four-way The Flash, Supergirl, Arrow and Legends of Tomorrow crossover originates in Central City. The event will take place in November during the week of Arrow’ s 100th episode, Season 5 episode 8. However, The Flash Season 3 episode 7, which just so happens to be directed by Kevin Smith, may set everything up.

Smith suspiciously confirmed Doctor Alchemy will appear in his episode on Twitter last week. While it’s still unknown if the villain will be introduced before then (and if his unknown identity is the alter-ego of Tom Felton’s character, Julian Dorn), this could mean Doctor Alchemy will be the crossover event’s big bad.

In a long-winded post on Instagram, Smith described The Flash Season 3 episode 7 as “the calm before the storm that is the forthcoming crossovers between Supergirl, Legends of Tomorrow, and Arrow.” Calm before the storm is an interesting phrase considering the episode is set to feature Doctor Alchemy… whose presence should make things anything but calm.

The photo Smith posted is a selfie with Felton, which may not be a coincidence if his character turns out to be Alchemy. The two had just finished shooting what Smith describes as a “moody scene with Tom and Grant Gustin.”

“I've seen what they've got planned for the massive event and it fucking RULES!” Smith continued in the post. “It's breathtaking in its enormity and will be particularly fun for any long term @dccomics fan like me who has been reading that company's books for decades. They're pulling elements from a story that was a favorite of mine back in the day so there are tremendous terms and legendary locations in the crossover script I saw that will make any #dccomics lover fill their Underoos! I have enjoyed the shit out of "directing" Season 3 Episode 7 - but as a fan of #TheFlash , I can't wait to watch the crossover to come!”

What’s odd, though, is the Kevin Smith-directed episode is titled ‘Killer Frost.’ If you’re caught up with The Flash Season 2, you remember Caitlin Snow met her Earth-2 doppleganger in Zoom’s lair -- the icy sharp-tempered metahuman named Killer Frost with a past all too similar to her own. Earth-1 Caitlin’s alter-ego as Killer Frost was teased many times in Season 2 as her character hardened up after the whole Jay Garrick kidnapping situation. Interestingly enough, Executive Producer Andrew Kreisberg revealed last year that Caitlin’s origins will be heavily explored in Season 3. What’s more? Earth-2’s Killer Frost is technically dead. Whether Earth-1’s Caitlin Snow will becomes Killer Frost naturally, changes due to the Flashpoint timeline, or it’s someone else entirely remains to be seen.

Recent reports also indicate the Arrow crossover episode has a lot of surprises. Robert Queen and Black Canary, both dead, are confirmed to return for Season 5 episode 8 amidst the crossover. Series creator Marc Guggenheim specified Robert Queen’s appearance is neither Flashpoint nor Flashback related. Along with Anthony Venza, Stephen Amell also revealed there is another mystery character coming to the episode.

Regardless of whether Arrow’ s crossover episode holds the most surprises, The Flash is the show that has the most wiggle room to connect all four DC TV shows together across the Arrowverse. Robert Queen and Black Canary rising from the dead wouldn’t be a surprise for Arrow fans, but both of them (and the late Killer Frost) coming back at the same time has to have something to do with an arc originating on The Flash. Any ideas? Let us know in the comments below!

The Flash returns Oct. 4.