Nash devises a high-risk plan as he tries to help The Flash regain his speed. Meanwhile, Barry tries to reason with Eva McCulloch to release his wife from the Mirrorverse.
As Barry continues his attempts to save Iris, he suddenly realizes that he's acquired the power of speed thinking, which Cisco remains leery of. Meanwhile, Eva is forced to confront a terrible situation.
As Eva gains more power, Barry and his crew try to put an end to her actions, and in the process, a friend puts her own life on the line.
Seeking to avenge his family, Abra Kadabra comes back with an evil plan in mind, all the while a terrible monster terrorizes Central City.
Central City is attacked by a new reprobate called Psych, who makes the people of the city live in perpetual fear through ceaseless nightmares.
While installing a device they've invented, Cisco and Chester end up stuck in a time loop in 1998. They discover that the only way out is for Chester to visit his childhood home, which is more difficult than it seems.
As Kramer issues a warrant for Frost's arrest, after the latter was framed for murder, she sets out to find the killer and prove her innocence. Meanwhile, Barry receives an unexpected guest.
Caitlin tries to save her sister, as Kramer tries to make Frost choose between the metahuman cure and prison, while Barry and Nora set out to fight Fuerza.
With Barry feeling shocked and betrayed, he enlists the help of Timeless Wells. Iris's attempts to find answers put her and Team Citizen in the path of Psych.
Iris gets in over her head, as she finds out about Psych's identity and troubled past. Barry's attempts to have Fuerza battle Psych prove to be dangerous.
With a deadly force threatening Central City, Barry and Iris team up to protect the city from impending doom.
As Cisco and Kamilla announce that they're moving to Star City, a new version of Rainbow Raider wreaks havoc in Central City, forcing Team Flash to come together to stop her.
After being trapped in a mindscape by Psycho-Pirate, who uses a mask to acquire increased psychic powers, Cecile is forced to confront past memories, while Barry and the team try to help her.
As Allegra's cousin, Ultraviolet, comes back to the city, Allegra sets out to find her and make her change her ways. Joe uncovers a shocking secret about Kristen Kramer.
Barry's plans to start a family with Iris are interrupted, as a group of Godspeed drones strikes the city, targeting him. Chillblaine gets out of prison, assuring a skeptical Frost that he's changed.
John Diggle comes to Central City to try and help Barry take on the Godspeed drones. Meanwhile, Kramer and Joe are attacked by Creyke, a former associate of Kramer's.
Barry and Iris are united with their future children, as the battle with the Godspeed drones escalates, posing a threat to them all as well as everyone in the city.
Barry, Team Flash, along with Bart, Nora, and Iris join forces to take on the deadly supervillain Godspeed, who demands organic speed in return for ending the war.