Barry Allen (Grant Gustin) lived a normal life as a perpetually tardy C.S.I. in the Central City Police Department. His life changed forever when the S.T.A.R. Labs Particle Accelerator exploded, creating a dark-matter lightning storm that struck Barry, bestowing him with super-speed and making him the fastest man alive - The Flash.
But Barry wasn't the only person who was given extraordinary abilities that night; the dark matter also created meta-humans, many of whom have wreaked havoc on the city. New threats also arrived from a parallel earth known as Earth-2, under the direction of an evil speedster named Zoom (Teddy Sears).
With the help of his adoptive father, Joe West (Jesse L. Martin), his lifelong best friend and love interest Iris West (Candice Patton), and his scientist friends at S.T.A.R Labs, Caitlin Snow (Danielle Panabaker) and Cisco Ramon (Carlos Valdes), as well as Harrison Wells (Tom Cavanaugh) from Earth-2, Barry continues to protect the people of Central City from these powerful threats.
As Season 3 begins, Barry is living his dream life - his parents are alive, he's asked Iris on a date and he can finally be a normal guy as Central City has another speedster, Kid Flash (Keiynan Lonsdale), running around saving the city.
When Barry starts forgetting parts of his old life, the Reverse Flash (guest star Matt Letscher) taunts his nemesis and tells him that there will be serious repercussions for Barry and the ones he loves if he continues to live in this alternate universe.
In addition to losing his memories, his powers will also start to fade. When disaster strikes, Barry must decide if he wants to continue to live in this world as Barry Allen or return to his universe as The Flash.
Based on the characters from DC, The Flash is from by Bonanza Productions Inc. in association with Berlanti Productions and Warner Bros. Television, with executive producers Greg Berlanti (Arrow, Supergirl), Andrew Kreisberg (Arrow, The Flash), Sarah Schechter (Arrow, DC's Legends of Tomorrow) and Aaron and Todd Helbing (Black Sails).