After a particle accelerator causes a freak storm, CSI Investigator Barry Allen is struck by lightning and falls into a coma. Months later he awakens with the power of super speed, granting him the ability to move through Central City like an unseen guardian angel. Though initially excited by his newfound powers, Barry is shocked to discover he is not the only "meta-human" who was created in the wake of the accelerator explosion -- and not everyone is using their new powers for good. Barry partners with S.T.A.R. Labs and dedicates his life to protect the innocent. For now, only a few close friends and associates know that Barry is literally the fastest man alive, but it won't be long before the world learns what Barry Allen has become...The Flash.
When an experiment to save Barry's speed backfires, Nash Wells searches for a way to save The Flash and comes up with a dangerous plan. Meanwhile, Iris makes a startling realization inside the Mirrorverse and Cecile faces off with Rosa Dillon.
When Barry suddenly gains the power of speed thinking, he attempts to use his new gift to save Iris. While Barry is thrilled with his new power, Cisco is hesitant to trust it. Meanwhile, Eva must face a shattering truth.
As Eva becomes more powerful, Barry and team must find a way to stop her. They are shocked when an old friend - Sue Dearbon risks her life to help.
The Flash must deal with Abra Kadabra's sudden return to Central City. The villain is back with a vengeance and a score to settle. Meanwhile, Allegra deals with a tricky situation and Caitlin suspects something is off with Frost. Iris is forced to look at a dark moment in her past.
When a powerful new villain, Psych, channels and amplifies everyone's fears in order to wreak havoc on Central City, Barry realizes, with Cecile's help, that he must face his own worst fear in order to beat this new threat. Meanwhile, Joe is surprised when Kristen Kramer from the Governor's Municipal Logistics Commission drops into CCPD for a visit. Iris warns her father to dig deeper on why Kristen is actually there. Caitlin and Frost argue about how to live their lives.
Cisco and Chester travel back in time and get stuck in 1998, repeating the same day over and over again. The key to returning home is at Chester's childhood home but he refuses to visit.
When a mysterious ice powered enemy frames Frost for a brutal crime, she must find a way to clear her name; Barry and Iris have a surprise houseguest, and Joe continues to deal with Kristen Kramer.
With Frost facing an unjust punishment for her past crimes, Caitlin goes to great lengths to save her sister. Meanwhile, Barry's efforts to protect Speed Force Nora lead to a shocking discovery.
After a devastating betrayal, Barry turns to Timeless Wells for help. Meanwhile, Iris leads Team Citizen down a dangerous road in search of answers, and Cisco confides his biggest fear to Kamilla.
Iris is pushed to the limit as she seeks to uncover the mysterious truth about Psych; Barry initiates a new training system, that could potentially backfire, with devastating consequences; Joe and Cisco make life-altering decisions.
Barry and Iris come together to try and stop a dangerous force from destroying Central City.