Barry and the S.T.A.R. Labs team hunt down The Turtle, who steals kinetic energy. Barry faces a choice on whether or not he should reveal his secret identity to Patty.
Dr. Wells figures out how to induce Cisco's ability; they hence learn that Eobard Thawne is still alive. Iris says farewell to her mother. Patty realizes there's more to Barry than meets the eye.
Barry tries to team up with Dr. Harrison but finds out Harrison prefers working alone. The Flash fights a new meta-human. Iris researches her brother's drag racing. Dr. Harrison starts stealing Barry's speed.
Harrison, Cisco and Barry travel to Earth-2 to save Harrison's daughter. Barry assumes the role of his doppelganger, who's married to Iris. He then encounters alternate-Caitlin and alternate-Ronnie, who are Zoom's agents.
On Earth-2, the team asks for help from an unexpected source to find Zoom's lair, while on Earth-1, Caitlin tries to perfect Velocity-9 so Jay can stop the Geomancer.
When King Shark escapes from an A.R.G.U.S. holding tank, Lyla and Diggle travel to Central City to warn The Flash. King Shark shows up at the West house and attacks Joe, Iris, Wally and Barry.
Just as Wells comes up with a plan to defeat Zoom, Zoom returns hellbent on destroying Central City. Meanwhile, Cisco has a vision of his brother, and Iris comes to terms with her feelings.
Zoom unleashes an army of Earth-2 meta-humans, the leader of which is Black Canary's doppelganger, Black Siren; Joe worries when Wally goes out to help The Flash.
The Reverse-Flash taunts The Flash and warns of repercussions if Barry continues to forget his old life. When disaster strikes, Barry must decide whether to live as Barry Allen or return to his universe as The Flash.
Barry discovers that the effects from Flashpoint are greater than he thought. In the meantime, he meets his new co-worker who has an immediate disdain for him.
Mirror Master joins his old partner, Top, and looks to even the score with Snart; Jesse joins the chase, but her decision to defy one of Barry's orders results in terrible consequences.
Caitlin visits her mother to help her understand her growing meta-human powers; Barry tries to convince Julian to let him help investigate a new meta-human attacking Central City.
Wally starts to have visions of him being Kid Flash so Barry tells him the truth about his powers in Flashpoint. Meanwhile, the rest of the group find out about Caitlin's Killer Frost powers.
Barry asks Green Arrow for help when aliens attack Central City, but when they realize that won't be enough, they bring the Legends and Supergirl in on the battle.
Barry heads to Earth Three to get advice from Jay Garrick on how to stop Savitar. Wally tells Barry that he has been training with H.R.. Old wounds are reopened as Cisco faces Christmas without Dante.