Barry (Grant Gustin) is back from his trip to the Speed Force as of "The Flash" Season 2 episode 22, and it looks like the short stay has made him a lot more confident, a tad bit more than his friends are comfortable with. Meanwhile, Zoom (Teddy Sears) unleashes an army of meta-humans from Earth-2 in Central City, and to the utter dismay of Team Flash, these supervillains are led by Laurel's (Katie Cassidy) evil doppelganger Black Siren.
The news of Laurel's death is still fresh for all the members of Team Flash, and it seems like Black Siren knows this too. She might use this knowledge to her advantage in "Invincible." It is definitely not an easy job to fight a villain who looks eerily similar to a dearly departed, especially when their departure is still fresh.
It seems like Black Siren is also bringing back some of the meta-humans from Earth-2 back from the dead, namely, Caitlin's doppelganger Killer Frost (Danielle Panabaker) and Cisco's lookalike Reverb (Carlos Valdes). They are seen together in the images from the upcoming episode shared by Melty. However, this does not necessarily mean they are brought back from the dead, it may be images of a flashback, which adds revenge as an inspiration to Black Siren's mission to destroy Central City and thereby Team Flash.
It also does not help that Barry behaves too overconfident for Cisco's liking, and the others sharing the same sentiment. Barry believes that the Speed Force, and by default, the Universe, wants him to defeat Zoom, which he interprets to mean that he will defeat Zoom. "I know from being in the Speed Force that the Universe is with us. How could we possibly lose?" Barry asks in "Invincible," while also declaring that he is no longer afraid.
While it may be true that it is Barry's destiny to defeat Zoom, he still has no control over the casualties of the war. Cisco even sees visions of a possible apocalypse, meaning anything could happen in the next two episodes of Season 2. In the promo for Season 2 episode 22, Zoom tells Barry, "You always have to be the hero. While you're playing the good little boy, I'll be busy winning."
A very popular fan theory based on this scene is that Zoom may kill Barry's father Henry (John Wesley Shipp) to teach Barry that he will always have an upper hand over him. In the promo, we also see Zoom creating a hole in the multi-verse by seemingly punching thin air. It just proves to show that Barry is still much less powerful than his nemesis.
Here is the official synopsis for Season 2 episode 22 of "The Flash:"
Zoom unleashes an army of Earth-2 meta-humans, the leader of which is Black Canary's doppelganger, Black Siren; Joe worries when Wally goes out to help The Flash.