Ronnie and Stein turn into Firestorm and help Barry destroy the singularity, but at the cost of Ronnie's life. Six months later, Barry operates alone, using his speed to repair Central City while being embraced by the public as a hero; Cisco works in the police department alongside Joe, and Caitlin works at Mercury Labs. Barry evaluates a crime scene with a victim named Al Rothstein. At a ceremony, the Flash is attacked by Atom-Smasher, whose strength and size manipulation prove too much for Bar
Jay explains to everyone that he is the Flash on a parallel Earth and that he was in a battle with a demonic speedster named Zoom when the singularity brought him to this Earth without his powers. Stein confirms the claim, describing their world as "Earth-1" and Jay's as "Earth-2". Zoom brings another metahuman from Earth-2 called Sand Demon, later identified as Eddie Slick, to kill the Flash. Cisco analyzes the "sand" left behind and has a vision of the previous fight, frightening him. After Sl
Jay creates a device that stabilizes the singularity and will allow him to return home, but he opts to stay to help Barry stop Zoom. Meanwhile, Lisa Snart shows up asking for Flash's help in rescuing Snart, whom she believes was kidnapped. Barry tracks down Snart, who is revealed not to be kidnapped but is working with his father, Lewis. Lisa states that Snart would never work with Lewis willingly, because the latter was abusive toward her when she was a child. Eventually, the team determines th
The team is able to temporarily stabilize Stein. Caitlin states that he needs to merge with a new person in order to survive. She identifies two potential candidates: a scientist named Henry Hewitt and a former high school football star named Jefferson Jackson. Hewitt is excited to merge with Stein, but the attempt fails and Hewitt leaves angrily, not knowing that his own metahuman powers have been activated. Jefferson initially refuses, but agrees when Hewitt goes on rampage. After the successf
Wells, who Cisco nicknames "Harry" to distinguish him from Thawne, reveals that he is responsible for the creation of the metahumans and Zoom on Earth-2. He states that he plans to help Barry's team stop Zoom and other metahumans. At the same time, a metahuman from Earth-2 called Doctor Light arrives and starts robbing banks. Barry recognizes her as the Earth-2 version of Linda. Later, Light attempts to kill Linda and take over her identity, but accidentally kills Linda's boss and is stopped by
As the team works to find a way to stop Zoom, Doctor Light escapes from her containment cell. Instead, the Earth-1 Linda agrees to help the team by impersonating Doctor Light. Barry reveals his alter ego to Linda. Harry creates a speed dampening serum and the team stages a fight at one of the breaches in order to trick Zoom through. The attempt fails, as Zoom knew the plan. Instead, he goes after Linda, before fighting Barry. Zoom is much faster and easily overpowers Barry, showing him defeated
Barry manages to recover from the paralysis, but is unable to use his powers due to the psychological trauma of Zoom exposing Barry's defeat to the city. Iris reaches out to Henry, who returns to help Barry overcome his fears. Wells formulates a plan to close all of the breaches, except one, through which Zoom can enter into the trap set for him. Cisco touches Kendra, but leaves after seeing a winged person in a vibe. Grodd returns, using scientists to steal various chemicals in the hopes of cre
Vandal Savage arrives in Central City, seeking to kill Kendra. Barry goes to Star City and enlists the help of Oliver and his team to protect her. The team is visited by Malcolm who informs them that Savage is an immortal. Later, Kendra is kidnapped by Hawkman, but Barry and Oliver rescue her and capture Hawkman, who introducing himself as Carter Hall, tells them he and Kendra are soulmates who have been connected for millennia. The pair are destined to die, be reborn, and find each other in eac
Mardon breaks James Jesse and Snart out of Iron Heights in an effort to team up to kill the Flash. Snart declines and alerts Barry. Jesse and Mardon place bombs hidden in Christmas gifts throughout the city, threatening to set them off in family homes if Barry does not sacrifice himself. Wells, Cisco, and Jay find one of the bombs and alter its magnetic polarity; they send it into one of the dimensional breaches, which causes it to attract the remaining bombs, removing them from the city. With t
Cisco presents a new idea to slow Zoom down, telling the team about a metahuman, whom he has dubbed the "Turtle", who has the ability to stop the kinetic energy around him and slow everyone to a halt. After Barry fails to stop the Turtle, identified as Russell Glosson, at a diamond unveiling, the team sets a trap at an art exhibit. Barry invites Patty with the intention of telling her his secret, but Glosson is aware of the trap and almost kills Patty before escaping. Later, Glosson kidnaps Patt
The team discovers Turtle's death and Jay suspects Harry. Cisco asks Harry for help in controlling his vibing abilities. The latter determines they are connected to Cisco's fear response and triggers a vibe which alerts the team that Eobard Thawne is back. Harry surmises that this version of Thawne is from a point in the future before he went back in time to kill Nora and was protected from being erased. Cisco has a vibe of the future, and the team learns that Thawne is planning to use tachyons
Right before the particle accelerator explosion, Joey Monteleone was thrown into a tar pit and left for dead. Sealed away, he is freed two years later with the ability to turn his body into molten tar. He sets out to get revenge on those who attempted to kill him. Harry creates a device to siphon Barry's speed energy and attaches it to his suit. It steals a portion of Barry's speed. Wells gives the energy to Zoom, who demands the rest. Meanwhile, Wells and Barry also successfully find a way to c
Before heading to Earth-2, Barry closes all but one of the breaches, which is at S.T.A.R. Labs. Using the last breach, Barry, Cisco, and Harry travel to Earth-2, but an energy surge destabilizes the breach and the trio get stuck on Earth-2. Barry decides to impersonate his doppelgänger to get more information on Zoom. He later meets the Iris and Joe of Earth-2 and learns that Iris, who is his doppelgänger's wife, works for the CCPD while Joe is a singer. Barry is attacked by Earth-2's Caitlin an
On Earth-2, Zoom issues a demand to Central City to turn in Wells and attacks S.T.A.R. Labs to find Wells and Cisco; but the two escape with Barry-2. The trio updates Iris-2 on what happened with Barry-1. They decide to convince Caitlin-2 to help. After a fight, Caitlin-2 agrees to take the team to Zoom. They arrive and rescue Barry-1 and Jesse, but Zoom shows up too. They are able to escape by the help of Caitlin-2, who keeps Zoom frozen and unable to move, but a third unidentified prisoner, wh
While everyone tries to move on, the humanoid shark-monster that Harry stopped, known as "King Shark," escapes A.R.G.U.S. custody and heads for Central City to kill the Flash. John Diggle and Lyla Michaels, the new director, arrive to warn Barry. King Shark, later identified as Shay Lamden, shows up at Barry's home looking for the Flash, tracking Barry's electrical field. A.R.G.U.S. arrives and forces Shay to retreat. Later, Barry forces King Shark to chase him out on the water, where Barry crea
Barry starts training to get faster so that he can stop Zoom. While out with friends at a club for downtime, Barry and the other club patrons are robbed by an unknown speedster, who then escapes. The speedster turns out to be Eliza Harmon, a Mercury Labs employee who developed Velocity-9 from samples Caitlin gave her to help with Jay's illness. Operating under the alias "Trajectory", Harmon invades S.T.A.R. Labs, imprisons Barry, and demands more V-9. After she threatens Jesse's life, Wells and
Barry travels back in time to when Hartley Rathaway attacked the team, and switches places with his past self, in order to have Thawne help him solve the speed force equation. However, after a Time Wraith follows Barry to the past, Thawne deduces Barry's deception. Barry is able to convince Eobard to help him become faster. The wraith comes to the lab, where Caitlin and Cisco are forced to accept help from Hartley to deter the wraith. Afterward, the Barry from the current time arrives, forcing a
Years earlier on Earth-2, a young Hunter Zolomon watches as his father murders his mother and is subsequently sent to an orphanage. In the present day, Barry tests the tachyon accelerator, and is able to enhance his speed four times greater than normal. Barry decides to re-open a breach back to Earth-2, and he believes that Cisco's powers are the key to opening the portals. Meanwhile, Caitlin reveals that Jay's Earth-1 doppelgänger is Zolomon and Wells, shocked to hear this, reveals that Earth-2
As Barry adjusts to life without his powers, Wells decides to leave the lab to look for Jesse. Shortly after speaking with her, Wells is attacked and kidnapped by Griffin Grey, believing him to be Thawne, who demands that Wells find a cure for his metahuman abilities. Grey has superhuman strength, but is also aging rapidly. Barry discovers that, when Grey uses his super strength, he accelerates the aging process. Barry, Joe, Cisco and Jesse manipulate Grey into exerting his powers until he ages
While Barry keeps declining Harrison's offer, the team rigs a hologram of the Flash to stop crime around the city so that no one will know the truth. Henry returns to Central City and joins the team. He argues with Wells on the safety of another explosion. Hunter and Caitlin arrive back on Earth-1 with Hunter declaring the city under his control. Iris confesses her feelings to Barry. The Earth-2 version of Dante Ramon, called "Rupture", arrives on Earth-1 looking to kill Cisco, believing that Ci
Wally regains consciousness, but Jesse remains in a coma. Cisco has a vibe of Barry and realizes that he is still alive and in the speed force. Barry meets physical manifestations of the speed force in the form of faces familiar to him. The speed force informs Barry that he cannot leave unless he catches a mysterious moving figure, thus gaining his speed back. Cisco and Wells create a path into the speed force so Barry can escape, but the latter chooses to remain so he can earn his powers back.
Caitlin returns to the team, but not without emotional trauma from being kidnapped. Zoom's army wreaks havoc across the city. Barry puts out several fires and takes out some of the metahumans to help the police. Back at S.T.A.R. Labs, Barry displays a level of confidence in stopping Zoom that concerns the team and each of them attempts to convince him to be more cautious. Among the attackers is Laurel Lance's doppelgänger, "Black Siren", who attacks various buildings around Central City using so
Zolomon escapes Barry by creating a time remnant. After Henry's funeral, Hunter challenges Barry to a race to determine who is faster, threatening to kill everyone Barry loves if he refuses. Harrison discovers that Hunter has a magnetar, a device that will destroy every planet in the Multiverse except Earth-1 which requires both their speeds to power. When an enraged and vengeful Barry refuses to back out, the team locks him in the Pipeline and force Zolomon back to Earth-2 themselves; but Hunte