Barry is living his dream life – his parents are alive, he’s asked Iris West on a date and he can finally be a normal guy as Central City has another speedster, Kid Flash, running around saving the city. When Barry starts forgetting parts of his old life, the Reverse Flash taunts his nemesis and tells him that there will be serious repercussions for Barry and the ones he loves if he continues to live in this alternate universe. In addition to losing his memories, his powers will also start to
Barry and Team Flash are thrilled to reunite with Earth-2 Wells and Jesse. Wells confides to Barry and Caitlin that Jesse has all the powers of a speedster and has been saving people on his Earth. He is concerned about her safety and wants them to talk her out of using her powers. Meanwhile, Magenta, a new meta who can control metal, terrorizes the city.
Barry continues to train Jesse and when a new meta human, Mirror Master, appears on the scene he lets her tag along. Mirror Master has teamed up with his old partner, Top, and is looking for Snart to even a score. Jesse is quick to join the chase but defies one of Barry’s orders which results in disastrous consequences.
Caitlin goes to her mother to help understand the meta-human powers growing inside her. Meanwhile Barry tries to convince Julian to allow him to help investigate a new human meta-attack on Central City.
Caitlin uses her powers to save Barry but as her mother predicted, the effort unleashes her inner Killer Frost. Killer Frost goes on a rampage looking for Dr. Alchemy, kidnapping Julian and battling both The Flash and Vibe. Meanwhile, Joe and H.R. have a heart to heart talk.
When aliens called the Dominators attack Central City, Barry speeds over to Star City to ask the Green Arrow for help in stopping them. Realizing the battle against the Dominators is bigger than they thought, they track down the Legends of Tomorrow, and Barry and Cisco create a breach to bring back a secret weapon – Supergirl. Once all of the super friends are assembled, they come up with a plan to attack but a shocking secret related to Flashpoint is revealed and suddenly no one is sure who
With Alchemy and Savitar still looming threats, Barry is unable to focus on the Christmas holiday, and especially his relationship with Iris. Determined to stop Savitar, Barry goes to Earth-3 to get advice from Jay Garrick. Wally wants to help Barry fight Savitar and reveals that he’s been training with H.R, which doesn’t go over well with Barry. As Cisco faces his first Christmas without his brother Dante, old wounds are reopened.