Even though Barry (Grant Gustin) missed learning the truth about Harrison Wells (Tom Cavanagh) before accidentally jumping back in time, it won’t be long before The Flash‘s Scarlet Speedster finally discovers that his mentor also happens to be his mortal enemy.
“Barry is going to find out in the next couple of episodes,” Gustin reveals to EW. “Joe [Jesse L. Martin] and Barry refocus all of their energy on Wells.”
Barry will actually become suspicious of Wells as early as Tuesday’s episode, though Cavanagh cautions that the truth coming out won’t make Wells’ goal to get home more difficult to obtain. “Harrison Wells is not as dumb as he looks,” he says. “By that I mean things that perhaps seem accidental that we’ve been watching in the first 15 episodes have not been accidental. You don’t get to come back in time and travel back and forth unless you have a certain modicum of intelligence and have thought things through. What looks like discovery on the part of our dear friends, I would tease by saying it’s not so much discovery at all.”
The truth that Wells is the Reverse Flash will naturally be devastating to Barry, which makes his job in getting to the truth all the more difficult. “Barry still has a hard time not liking him, even after he learns the truth,” Gustin says. “In the moments he’s just with him and talking to him, Wells just is so helpful and supportive with Barry. It’s really hard and confusing and frustrating for Barry moving forward. Barry’s been a really bad liar all season, and this makes him have to get better at lying.”
Because Barry has traveled back in time, he will set off a series of events during Tuesday’s episode that ultimately alters what previously happened, much like a butterfly effect. “The first time something changes, the day starts to change,” Gustin says. “It starts as the same day, but it’s also not the same day pretty much right away, because Barry realizes what has happened and that in itself changed the course of the day.”
“It’s really important for Barry to know that [things can change] as he heads into the end of the year,” executive producer Greg Berlanti adds. “Our real goal with the episode, more than anything actually, was to establish the rules for our own show in terms of time travel and to introducing those elements and characters early enough into the DNA of what The Flash is, because I don’t think you can do a Flash show without dealing with time travel.”
Among the changes will likely be Iris (Candice Patton) admitting that she’s in love with Barry, which was born out of a sense of urgency while facing impending death. It sounds like she’ll even be unaware that Barry is actually The Flash, since Patton teases Iris will still be investigating the metahuman in coming episodes. “It’s a difficult dynamic between Iris and Barry, and also Iris and The Flash, she’s getting closer and closer to figuring it out and I think those questions will be answered by the end of the season for sure,” she teases.
Aside from Iris’ confession making things very awkward between Barry and Linda (Malese Jow), it could also threaten her own relationship with Eddie (Rick Cosnett), who is seen punching Barry in the face in the promo for Tuesday’s episode. “Eddie is not stupid,” Cosnett says. “He’s seeing that there’s something going on between them, but he’s not threatened by it. He’s not really a jealous person, he’s so secure with himself, which is more irritating to Barry. We’re going to see him unravel and come to fruition by the end of the season.”
The Flash airs Tuesdays at 8 p.m. ET on The CW.