After a thrilling cliffhanger last season which saw Mirror Monarch victorious and still-at-large in Central City, The Flash must regroup in order to stop her and find a way to make contact with his missing wife, Iris West-Allen. With help from the rest of Team Flash, Barry will ultimately defeat Mirror Master. But in doing so, he’ll also unleash an even more powerful and devastating threat on Central City: one that threatens to tear his team—and his marriage—apart.
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.
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.
Cisco and Kamilla tell the team they are leaving Central City. However, Barry, Iris and Caitlin don't have much time to digest the news because a new version of Rainbow Raider strikes and OG Team Flash must join together one final time to save the city.
Cecile is forced to confront her past in order to break free from a psychic prison. Meanwhile, Chester takes over for Cisco but makes a mistake that puts Barry in serious danger. Joe investigates Kristen Kramer's old military ties and discovers an unsettling truth.
When Ultraviolet returns to Central City, Allegra is determined to find her cousin and change her heart. Meanwhile, Joe finds evidence that Kristen Kramer may not be the good cop she appears to be.
When an army of Godspeeds attack Central City, Barry and Iris must put their family plans on hold and focus on the latest threat to their home. Meanwhile, Chillblaine is released from prison and claims to be reformed but Frost has her doubts.
John Diggle arrives in Central City with a weapon to help Barry stop the Godspeed War. Meanwhile, Allegra and Ultraviolet's new bond is put to the ultimate test, while Joe and Kristen Kramer are hunted by a former colleague of hers.
Barry and Iris greet their future children, XS and Bart, only for a shocking secret to threaten their new familial harmony. Meanwhile, the Godspeed war intensifies and threatens to destroy Central City.
The Flash enlists a host of speedster allies, including Iris and his children from the future - Bart and Nora West-Allen - to end the speedster war and defeat a deadly new adversary: the villainous Godspeed.