Grant Gustin
"The Flash" resumes this April 25 with "The Once and Future Flash," with Barry Allen journeying forward to unmask the speed demon "Savitar." Reuters/Phil McCarten

"The Flash" resumes this April 25 with "The Once and Future Flash," the part where Barry Allen (Grant Gustin) fast-forwards into the future to try and save Iris West (Candice Patton). A trailer has been released for the upcoming episode, revealing some changes to Team Flash and the return of two villains.

The decision to travel forward

"The Flash" came up with the idea to head to the future after getting nothing out of the villain of episode 18, "Abra Kadabra." The villain was portrayed by David Dastmachian, a new pawn in the Savitar puzzle. He claims to know the true identity of the speed demon and would only divulge it if he were set free, Entertainment Weekly reported.

Joe West (Jesse L. Martin) took the chance but things got a bit complicated with "Gypsy" (Cindy Reynolds) appearing at the scene. With that try foiled, in comes the plan of Barry to run to the future to find out who "Savitar" really is.

The changes in the future

Based on the 30-second trailer that came out, some of the members of Team Flash look different. The future Barry Allen looks miserable and sports long hair, Wally West (Keiynan Lonsdale) is in a wheelchair and “Killer Frost” (Danielle Panabaker) is still at large, according to Screen Rant.

Aside from those cast members, there are returning villains in the mix. "Mirror Master" (Grey Damon) and the "Top" (Ashley Rickards) are back, something that could be a result of an altered timeline. From the looks of it, metahumans may have broken out of prison and ran amok with the Central City hero gone. Could this be related to the headline where The Flash vanishes?

With the changes, there are some speculations on why the future Barry Allen and Wally West are what they are. The long-haired Barry is likely an off-shoot from the death of Iris, while Wally’s state could be a result of some interference against Savitar.

At some point, the current state of the future could be a result of Barry’s inability to safeguard his friends and Central City, plus the likeliness of being stuck in the future. If so, fast-forwarding could be a costly move where Barry will be forced into a corner and make sure he can still travel back to avoid yet another round of changes on his actual Earth.

Above all, it will be interesting if Barry will finally unmask who Savitar really is. Now that he knows that the villain is not a god but a person. There are suggestions that it could be a future version of Wally or maybe even Barry himself, according to another report from Entertainment Weekly. He could be anyone as show producer Andrew Kreisberg put it, "You're definitely going to cry."

"The Flash" returns on April 25 with "The Once and Future Flash" on The CW and will be shown via Fox8 for Australian viewers. Check out the trailer below for some of the highlights of the upcoming episode.