Series overview
Season 12345678
"You may be the fastest man alive, Allen. I'm the fastest mind."
"So this is how we begin whatever twisted game you have planned."
"No, Mr. Allen. You've already lost and never even realized it.
Clifford DeVoe and Barry Allen[src]

The fourth season of The Flash​​​ premiered on October 10, 2017, on The CW and concluded on May 22, 2018. The season consisted of 23 episodes.



Main cast

Recurring cast


# Episode name Directed by Story by Teleplay by Original airdate
1 "The Flash Reborn" Glen Winter Andrew Kreisberg Todd Helbing & Eric Wallace October 10, 2017
With Barry in the speed force, Iris, Kid Flash, Joe and Vibe have taken over protecting Central City. However, when a powerful armored villain threatens to level the city if The Flash doesn't appear, Cisco makes a risky decision to break Barry out of the speed force. However, the Barry that comes out isn't the same Barry that went in.
2 "Mixed Signals" Alexandra La Roche Jonathan Butler & Gabriel Garza October 17, 2017
Barry has his hands full when he takes on a dangerous meta who can control technology, while also confronting an obstacle in his personal life; the ramifications of abandoning Iris for six months to balance the Speed Force. Meanwhile, Gypsy breaches in for a hot date with Cisco, but she gets annoyed when his work keeps them apart.
3 "Luck Be a Lady" Armen V. Kevorkian Sam Chalsen & Judalina Neira October 24, 2017
Barry and the team are hit by a string of bad luck and realize it is the handiwork of a new meta, Becky nicknamed Hazard, who has the ability to give others bad luck, while cashing in the benefits for herself. Meanwhile, Harry Wells returns to Earth-1 to give Wally a message from Jesse.
4 "Elongated Journey Into Night" Tom Cavanagh Sterling Gates & Thomas Pound October 31, 2017
Cisco is shocked when Gypsy's father, Breacher, shows up on Earth-1. Breacher takes an immediate disliking to Cisco and decides to hunt him. Meanwhile, Barry runs into his old nemesis, Ralph Dibny.
5 "Girls Night Out" Laura Belsey Lauren Certo & Kristen Kim November 7, 2017
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.
6 "When Harry Met Harry..." Brent Crowell Jonathan Butler & Gabriel Garza November 14, 2017
When collectors of Native American artifacts are attacked by a meta named Mina Chayton who can bring inanimate objects to life, Barry turns to a surprising ally for help. Determined to crack the identity of The Thinker, Harry enlists Cisco’s help to summon the ultimate think tank; "The Council of Wells", a roundtable of the brightest Harrison Wells’ from various Earths.
7 "Therefore I Am" David McWhirter Eric Wallace & Thomas Pound November 21, 2017
Barry comes face to face with DeVoe. DeVoe's past is revealed through flashbacks. Meanwhile, Iris puts the final touches on the wedding, which is a week away.
8 "Crisis on Earth-X, Part 3" Dermott Downs Andrew Kreisberg & Marc Guggenheim Todd Helbing November 28, 2017
Barry and Iris's wedding brings the gang together, but things go awry when villains from Earth-X attack the ceremony. All of the superheroes band together with help from their super friends like Citizen Cold, The Ray, Felicity Smoak, Iris West and Alex Danvers to take on their most formidable villains yet. Earth's mightiest heroes - Green Arrow, Supergirl, The Flash and White Canary - lead their teams into battle to save the world.
9 "Don't Run" Stefan Pleszczynski Sam Chalsen & Judalina Neira December 5, 2017
Amunet kidnaps Caitlin and puts meta-dampener handcuffs on her to keep her from turning into Killer Frost. Amunet tells Caitlin she needs her to perform a tricky medical task and if Caitlin fails, Amunet will kill her. Meanwhile, The Thinker traps The Flash in a speedster-proof prison. With the clock ticking, The Team doesn't have the time or resources to track both Caitlin and Barry so Iris is forced to choose who to save.
10 "The Trial of The Flash" Philip Chipera Lauren Certo & Kristen Kim January 16, 2018
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.
11 "The Elongated Knight Rises" Alexandra La Roche Sterling Gates & Thomas Pound January 23, 2018
When a familiar villain returns to terrorize Central City, Ralph must rise up to defend the innocent while Barry is detained by his trial. Meanwhile, Barry searches for the strength to keep his optimism alive in the face of his new circumstances.
12 "Honey, I Shrunk Team Flash" Chris Peppe Sam Chalsen & Judalina Neira January 30, 2018
A meta who can shrink anything he touches battles Team Flash. Cisco and Ralph get caught in his crossfire and are shrunk to miniature versions of themselves. Cecile realizes her pregnancy has caused her to have temporary powers and discovers she can hear other people's thoughts, which unnerves Joe. Meanwhile, Barry meets someone with a mysterious connection to Henry Allen.
13 "True Colors" Tara Nicole Weyr Jonathan Butler & Gabriel Garza February 6, 2018
After hearing that Amunet has struck a deal to buy all of the metahumans in Iron Heights, Barry must decide if he should expose his powers in order to save his cellmates. After a visit from an old friend, Ralph is reminded of his shady past and wonders if he's really a changed man.
14 "Subject 9" Ralph Hemecker Mike Alber & Gabe Snyder February 27, 2018
Barry meets a powerful woman whose abilities could help him in his battle with DeVoe. Meanwhile, after learning that DeVoe is targeting everyone who was on the bus, Ralph decides he doesn't want to be a hero anymore, his only concern is staying alive. Harry offers to help Joe.
15 "Enter Flashtime" Gregory Smith Todd Helbing & Sterling Gates March 6, 2018
When a nuclear bomb detonates in downtown Central City, Barry, Jesse Quick and Jay Garrick slow down time by entering Flashtime. As everyone in the city is frozen, the three speedsters push themselves to the breaking point to save the city and everyone in it.
16 "Run, Iris, Run" Harry Jierjian Eric Wallace March 13, 2018
Team Flash confronts a new bus meta, Matthew AKA Melting Point, with the ability to swap people's DNA. During a battle with Team Flash, Matthew transfers Barry's super speed to Iris. Now, with a new threat unleashed on Central City, Barry must act as the team leader while Iris takes on the mantle of superhero speedster in order to defeat their new foe.
17 "Null and Annoyed" Kevin Smith Lauren Certo & Kristen Kim April 10, 2018
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.
18 "Lose Yourself" Hanelle Culpepper Jonathan Butler & Gabriel Garza April 17, 2018
When Barry and Team Flash find a way to enter the Thinker's lair, Ralph considers crossing a dangerous line to defeat DeVoe. Meanwhile, Joe is concerned by Harry’s recent behavior.
19 "Fury Rogue" Rachel Talalay Joshua V. Gilbert & Jeff Hersh April 24, 2018
When Barry needs help transporting a dangerous meta, he calls on a new friend for help - Citizen Cold; Cisco becomes suspicious of Harry.
20 "Therefore She Is" Rob J. Greenlea Sterling Gates & Thomas Pound May 1, 2018
Barry and Team Flash team up with Gypsy to try to thwart the Thinker's plan. Meanwhile, Cisco and Gypsy have a heart to heart talk about their relationship.
21 "Harry and the Harrisons" Kevin Mock Judalina Neira & Lauren Certo May 8, 2018
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".
22 "Think Fast" Viet Nguyen Sam Chalsen & Kristen Kim May 15, 2018
When DeVoe assaults an A.R.G.U.S. facility to complete his Enlightenment Machine, Barry realizes the only way he can stop him is if he allows Cisco and Caitlin to accompany him into the facility. Still shaken by Ralph's death, Barry isn't sure he wants to risk any more of his friends' lives and considers taking on DeVoe solo.
23 "We Are The Flash" David McWhirter Todd Helbing & Eric Wallace May 22, 2018
Team Flash gets help from a surprising ally in their battle against DeVoe.



Title cards

Promotional images



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