Having arrived in town intent on creating maximum chaos, Trajectory's antics are misinterpreted as having been perpetrated by the Flash himself. Barry thus must quickly uncover the mystery of who is the girl under the mask — as well as what is driving her mad desire for speed and destruction.

Zoom arrives back on Earth-1 intent on taking over Central City. Barry and Wells come up with a plan to stop Zoom once and for all but it’s extremely dangerous. Unsure if he should take the risk, Barry reaches out to both fathers for advice. Henry is adamantly opposed to Barry risking his life again but Joe thinks he can handle it which puts the two men at odds with each other. Meanwhile, Cisco is shocked when he vibes the Earth-2 villain Rupture, who happens to be his brother Dante’s doppelganger. Rupture came to this Earth seeking justice for Reverb’s death. Iris decides she’s finally ready to open up to Barry about her feelings for him.

Barry takes drastic measures to stop Savitar. Meanwhile, H.R. continues to push Tracy Brand to design the trap for Savitar and Killer Frost returns with an interesting proposal.

Having received an ominous threat from her old boss, Amunet, Caitlin fears that her past time as Killer Frost may be back to haunt her. Felicity comes to Central City to help the girls celebrate Iris's bachelorette party, while Cisco, Joe and the guys take Barry out for a night on the town.

As Barry’s trial for the murder of Clifford DeVoe begins, Iris and Joe must decide how far they are willing to go to keep Barry out of prison.

Barry and Ralph take different approaches to finding the remaining bus metas before DeVoe gets to them. However, Ralph's cavalier attitude frustrates Barry and the two clash over what it means to be a hero. Meanwhile, Breacher returns to ask Cisco for a favor.

With DeVoe's Enlightenment device nearly complete, in order to disable it The Flash and his team must put their faith in an unlikely ally – Amunet Black. Meanwhile, Harry hits an all-time low when the "Council of Wells" kicks him out but then Cisco introduces him to the "Council of Harrisons."

Barry and Iris face the ultimate parenting test when Team Flash battles Spin, a savvy millennial armed with meta tech, and a dangerous agenda for their daughter, Nora. Ralph is feeling defeated until an unlikely source issues a challenge to help boost his confidence.

Barry and Team Flash come up with a plan to stop Cicada. However, the plan calls for Barry and Nora to travel back in time to gather some key necessities. However, Barry hesitates, concerned about his daughter seeing certain parts of his life. Meanwhile, Sherloque takes his concerns about Nora to Iris, and Caitlin turns up a key asset in the fight against Cicada.

When Gorilla Grodd attacks Central City, Barry and Team Flash find themselves teaming up with an unexpected ally to defeat – King Shark. However, when they hit a snag, they bring in Dr. Tanya Lamden to try to reach the man behind the shark, Shay Lamden.

Barry's efforts to prepare Cisco for Crisis are derailed when Cisco schemes to save Barry's life instead. Meanwhile, Ramsey Rosso uses his deadly new abilities to save his own life, while sacrificing his humanity in the process.

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.

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.