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

Barry Allen will race through time during an upcoming episode of The Flash—though he may pay a price for it.

“There’s an episode coming up where there is inadvertent connection to the Speed Force that results in probably our funniest hour as well as our darkest hour as the dangers of time travel come to light,” executive producer Andrew Kreisberg tells EW. “It’s a mashup between Back to the Future and Terminator—the good version of time travel and the bad version of time travel.”

The episode will also be influenced by the 1993 flick Groundhog Day, in which Bill Murray’s harried weatherman relives the same day over again until he gets his priorities straight. “It’s a complete accident the first time [he time travels],” star Grant Gustin says. “It’s really confusing because now we’re playing with timelines and we’re having to shoot things a couple different ways. It’s like a Groundhog Day-type element. It’s really funny and really exciting.”

Initially, Barry doesn’t understand what’s happening and he’s the only one aware of the time travel situation. “He’s not handling it incredibly well. It’s freaking him out a little bit,” Gustin says. The others will eventually figure it out, which leads to some comedy when Cisco (Carlos Valdes) has to explain what’s going on to Joe (Jesse L. Martin) in terms of time travel films.

But once Barry figures it out, he’ll decidedly use time travel to his advantage. “He realizes, ‘Holy shit, this an opportunity to change things with my family’s past,'” Gustin says. “He doesn’t know yet to maybe not do that, but that’s where Barry’s at when he realizes what he’s just learned that he can do, that he can maybe save his mom.”

With that being said, it’s been suspected since the pilot episode that Barry may have been present the night his mother was murdered by the Reverse Flash—especially considering young Barry was suddenly and mysteriously whisked away from the house. Did Barry protect his younger self from the wrath of the Reverse Flash? “That’s a good theory,” Gustin says coyly.

But Kreisberg cautions that Barry tampering with the past “has massive repercussions for the show,” he says. “After that episode, things are never going to be the same on The Flash.”

The Flash airs Tuesdays at 8 p.m. ET on The CW.