‘The Flash’ Season 3 Episode 2 Spoilers: Barry’s Big Mistake Causes ‘Paradox;’ Killer Frost, Doctor Alchemy Coming?

"The Flash" season 3 episode 2 will show the massive paradox that came about due to Barry's (Gant Gustin) actions in the previous season's finale and this season's premiere, with a whole host of brand new troubles coming to chase the Scarlet Speedster for what he has done.

An advanced sneak peek of "The Flash" season 3 episode 2 was shared by Spoiler TV, showing the plot synopsis for "Paradox." In "The Flash" season 3 premiere, Barry eventually undid what he did in the season 2 finale that created the new "Flashpoint" reality only to realize at the end that not everything was completely back to normal as he might have thought.

One of the changes in "The Flash" Season 3 episode 2 "Paradox" is Iris' (Candice Patton) relationship with her Joe (Jesse L. Martin). In this new altered prime reality, Iris and Joe are apparently not on good terms with their relationship seemingly so bad even mentioning her in front of Joe will cause him to walk out of the room.

As shown in the promotional trailer for "The Flash" season 3 episode 2 released on The CW's official YouTube channel, another paradox in the episode is Cisco's apparently troubled new status. He was shown engaging in a support group in "Paradox," with Barry trying to understand exactly what it is that happened.

Felicity (Emily Bett Rickards) will also be making another guest appearance on the show in "The Flash" season 3 episode 2, asking Barry just what changed in this new paradox reality. New character Julian Albert will also be showing up, played by "Harry Potter" star Tom Felton as a regular main character, who will be Barry's new coworker with apparent disdain for him and likely the source of some new troubles.

Speaking of troubles, "The Flash" season 3 episode 2 will also see the first signs of Caitlin Snow (Danielle Panabaker) becoming Killer Frost in the prime reality of the show. Doctor Alchemy (Tobin Bell) will also be making an appearance in "Paradox," although still fully covered, and his plans for Edward Clariss (Todd Lasance) will likely be touched upon.

So just how big was Barry's mistake when he did and undid the "Flashpoint" reality? And how far did the paradox caused by his actions reach? Find out when "The Flash" season 3 episode 2 airs Tuesday, Oct. 11 at 8 p.m. ET on The CW.