Cisco is shocked when Gypsy's father, Breacher, shows up on Earth-1. Breacher takes an immediate disliking to Cisco and decides to hunt him. Meanwhile, Barry runs into his old nemesis, Ralph Dibny.

Barry comes face to face with DeVoe. Devoe's past is revealed through flashbacks. Meanwhile, Iris puts the final touches on the wedding, which is a week away.

When a familiar villain returns to terrorize Central City, Ralph must rise up to defend the innocent while Barry is detained by his trial. Meanwhile, Barry searches for the strength to keep his optimism alive in the face of his new circumstances.

Barry and Team Flash team up with Gypsy to try to thwart Thinker's plan. Meanwhile, Cisco and Gypsy have a heart to heart talk about their relationship.

Nora lets something slip about the future that devastates Iris. In an attempt to distract his wife, Barry asks Iris to team up to stop a new meta, Rag Doll. Meanwhile, Caitlin learns something about her father.

During a battle with Cicada, Nora is severely injured. Due to Cicada's dampening powers, Nora's speed healing isn't working, leaving Barry and Iris scared for their daughter's future. Upset about his injured child, The Flash is filled with rage and confronts Cicada in a brutal battle. Meanwhile, Killer Frost keeps interfering with Caitlin's work on the cure.

Team Flash is on high alert after Cicada II threatens to unleash a dangerous virus that would put all meta-humans at risk.

Knowing that Crisis is only weeks away, Barry prepares a member of Team Flash for life without him while hunting a terrifying meta-human with an unquenchable thirst. Meanwhile, Ralph uncovers a family secret.

Barry turns his attention to prepping Elongated Man for life after Crisis and without The Flash, but Ralph ultimately teaches Barry a lesson. Meanwhile, Cecile faces her own moment of self-discovery while helping a recuperated Chester P. Runk reclaim his identity.

After months of searching for Sue Dearbon, Ralph gets a lead on her whereabouts and finally comes face to face with his missing client. However, Sue refuses to return home to her family, and instead, takes Ralph on a daring adventure. Iris faces a new challenge while Barry considers a potentially dangerous request from a trusted source.

After Black Hole hires Rag Doll to kill Joe, Singh suggests he go into Witness Protection but Joe refuses to stop investigating Carver. While investigating Carver with Cisco, Ralph runs into Sue. Iris becomes suspicious of Eva.

After returning home from a visit for their parent's vow renewal, Bart and Nora quickly realize that things are not exactly as they left them. The duo race to repair any fissures in the timeline and restore everything back to the way it is supposed to be.

The Flash gets blasted with a shockwave forcing his body to age prematurely.

As Barry and Iris prepare for their new life, luck changes for those in Central City. Cecile takes on a case with Allegra's help, involving a string of unfortunate – and highly unexpected – events. Meanwhile, Chester and the team work with Khione to figure out her abilities.

As Iris receives word of a career milestone, Barry is suddenly nowhere to be found. In trying to get back home, Barry runs across many familiar faces. Khione continues to figure out her powers, and Chester works on a suit for Allegra.