Barry learns a new breacher, Dr. Light, has come through the portal and sets off to capture her. Jay tells Barry that Dr. Light was not a threat on Earth-2 and that Barry can reason with her. However, during a fight with The Flash, she blinds him and drops some shocking news about Zoom. Meanwhile, Barry and Patty go out on a date.

After recent events, Barry decides it’s time to confront Zoom and comes up with a dangerous plan. Caitlin sides with Jay and deems it too dangerous for Barry to engage with the speed demon. However, Iris shows her support and brings forth a surprising ally. We see what Earth-2 Harrison Wells’ life was like before coming through the breech.

When Mark Mardon AKA The Weather Wizard returns to break Leonard Snart AKA Captain Cold and James Jesse AKA The Trickster out of Iron Heights, Barry must stop these rogues from taking over Central City during Christmas. Meanwhile, Joe and Iris meet Wally West.

Barry, Wells and Cisco journey to Earth-2 to rescue Wells’ daughter, Jesse from Zoom. Barry is stunned when he runs into Earth-2 Iris and Joe, but nothing prepares him for meeting Killer Frost and Deathstorm. Meanwhile, back on Earth-1, Jay has to take over the Flash’s responsibilities when a meta-human nicknamed Geomancer attacks Central City.

On Earth-2, the team races to find Zoom's lair and asks for help from the most unexpected source. Meanwhile, back on Earth-1, Caitlin rushes to perfect Velocity-9 so that 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.

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.

A meta-human with super strength named Griffin Grey mistakes Harry for Earth-1 Harrison Wells and kidnaps him, demanding that Wells cure him from his current condition. Realizing another brilliant Wells could help track Griffin’s location, Barry asks Jesse to help. Meanwhile, Wally corners Joe about The Flash.

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.

With Barry gone, the team must figure out a way to handle the return of an old enemy - Girder. Realizing Girder is retracing his steps from his last attack, Iris volunteers to act as bait to trap him in S.T.A.R. Labs. Meanwhile, Barry fights to return to his old life.

After Zoom unleashes an army of Earth-2 meta-humans on Central City, Barry is shaken when he sees their leader is the Black Canary’s Earth-2 doppelganger, the Black Siren. Meanwhile, Wally takes to the streets to help The Flash stop the meta-humans, which worries Joe. Iris and Henry are concerned about Barry taking on Zoom.

After Zoom reveals his true plan, Barry vows to do whatever it takes to stop him.

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.