The Flash type TV Show network The CW genre Superhero Where to watch Close Streaming Options

As Zoom continues to send breachers from Earth-Two over to kill Barry Allen, The Flash’s titular hero will go on the offensive — but taking this villainous speedster down won’t be an easy feat.

“He’s got this demonic quality to him,” Grant Gustin tells EW. “As soon as Barry is face-to-face with him — like right in front of him battling with him — it becomes immediately clear to Barry, ‘Maybe I’m not ready for this.’ It’s pretty scary. It’s going to be one of the more disturbing things, I think, that the viewers will have seen happen to Barry. It’s not pretty. He’s much stronger and faster, and Barry’s not necessarily ready for this, but he thinks he is.”

Team Flash, however, doesn’t necessarily agree. Caitlin (Danielle Panabaker), in particular, sides with her potential new flame, Jay Garrick (Teddy Sears), who has since left Barry’s side because of the scarlet speedster’s eagerness to face Zoom. “She’s very cautious, particularly because she does have so much faith in Jay and so much trust in Jay, and he’s been so wary of Zoom,” Panabaker says. “She really takes that to heart. She is especially concerned with Barry taking on Zoom, because he’s so much of an unknown — his motivations are unclear. He’s already a darker villain than Reverse Flash was, so he’s clearly willing to go pretty far to get what he wants.”

Even Cisco (Carlos Valdes), who has always supported Barry’s decisions, will be concerned. ‘”It’s very clear in Tuesday’s episode that Zoom is not a threat to be taken lightly,” Valdes says. “Once the gravity of that hits the team, things start to change a little bit. In general, the team starts to separate themselves from the idea of Zoom for a little bit, because there’s such an apprehension and such a shock from what happens in coming episodes. It’s definitely a slow burn because of the magnitude of this evil. Cisco and Barry know together that the best way to take down this villain is to think things through, and to work together to really give it time, and to train.”

For one, Zoom definitely has a few tricks up his sleeve, like knowing that Barry previously dated Linda Park (Malese Jow), which would give our hero pause when facing her Earth-Two doppelgänger Dr. Light. “I would imagine it has a lot to do with time travel and the Speed Force,” Gustin says, shooting down any potential theories of a mole within Team Flash. “[Zoom’s] peeked into other timelines. He’s probably been trying to locate what timeline Barry’s actually from for a while now, and has peeked into other points of his life that Barry’s not even aware of or hasn’t even happened as far as this Barry’s concerned. Zoom has been planning this for quite a while and he’s much faster and much more powerful. He has his ways of peeking into Barry’s life at different points of his life without anyone being aware.”

Though, it does seem highly suspicious that Harry (Tom Cavanagh) has so much knowledge about speedsters if he wasn’t aligned with Zoom in the past. “If you created a speedster, you’d know about a speedster,” Cavanagh maintains. “I created one, so I could be one of the top few people on any Earth that knows what that means. It doesn’t align me with anybody.”

Answers in that regard may be coming since Tuesday’s episode will offer a peek at Harry’s life before he crossed over to Earth-One. “You’ve gotten a glimpse of what this guy’s life is like,” Cavanagh says. “Then you see this man in S.T.A.R. Labs on Earth-One, the same face and visage, clearly this man has had things stripped of him and now he’s down to priorities. A person who is cornered like that is going to act a different way… This version is all about getting what he needs. His whole life revolves around getting what he needs and nobody and nothing is going to stop him.”

As to whether Harry is, much like the other breachers, motivated to kill Barry for Zoom — like, say, to get his kidnapped daughter back? — Cavanagh scoffs. “If he’d been sent over to kill Barry, I don’t know that he wouldn’t have just let King Shark kill Barry,” he says.

The big question, though, is exactly who is Zoom? The theories fly fast on set. “I think it’s Felicity [Emily Bett Rickards],” Gustin jokes of Barry’s former Arrow flame. “A lot of people think it’s Henry Allen [John Wesley Shipp], some people think It’s Eddie Thawne [Rick Cosnett], some people think it’s Barry from Earth-Two.” Panabaker concurs: “I love the idea of it being Earth-Two Barry Allen. Selfishly, as actors, how fun would it be to get to do both extremes?”

“They’re really crafting the story lines in a way that make it so there are multiple people that have motives and multiple possibilities,” Valdes says. “The introduction of Earth-Two into our story is bringing all these different dimensions as far as possibilities are concerned. Anything can happen, and as a result of that, it keeps the audience and the actors on our toes.”

In truth, “There are infinite possibilities, really,” Gustin says. “It could really turn out to be a number of characters. To be honest, I don’t really know the answer, so I’m not sure.”

But there may be one cast member who knows Zoom’s true identity. “I don’t have a theory on it,” Cavanagh says cryptically. “Theoretical implies a whole different thing from fact.”

Who do you think is under Zoom’s mask? Find out when The Flash airs Tuesdays at 8 p.m. ET on The CW.