With Barry in the speed force, Iris, Kid Flash, Joe, and Vibe must protect Central City; a powerful armored villain threatens to level the city if the Flash doesn't appear; Cisco decides to break Barry out of the speed force.
Barry has his hands full when he takes on a dangerous meta who can control technology; Gypsy breaches in for a date with Cisco, getting annoyed when his work keeps them apart.
Barry and the team experience a string of bad luck and discover it is caused by a new metahuman; Harry Wells returns to Earth-1 to give Wally a message from Jesse.
Cisco is shocked when Gypsy's father shows up and takes an immediate disliking to Cisco; Barry runs into Ralph Dibny, his former nemesis.
Caitlin receives an ominous threat from her old boss; Felicity arrives to help the girls celebrate Iris's bachelorette party; Cisco, Joe, and the guys take Barry out for a night on the town.
When Native American artifact collectors are attacked by a meta who can bring inanimate objects to life, Barry turns to a surprising ally for help; Harry enlists Cisco's help to determine the identity of The Thinker.
Barry comes face to face with DeVoe; DeVoe's past is revealed; Iris puts the final touches on the wedding, only one week away.
Barry and Iris' wedding brings the gang together, but things go awry when villains from Earth-X attack the ceremony.
Amunet threatens to kill Caitlin if she doesn't help perform a tricky medical task; The Thinker traps The Flash in a speedster-proof prison; Iris is forced to choose whether to save Caitlin or Barry.
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.
A familiar villain returns to terrorize Central City; Ralph must rise up to defend the innocent while Barry is detained by his trial; Barry searches for the strength to keep his optimism alive in the face of his new circumstances.
A meta, who can shrink anything, leaves Cisco and Ralph as miniature versions of themselves; Cecile makes a discovery that unnerves Joe.
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 to save his cellmates.
Barry meets a powerful woman whose abilities could help him in his battle with DeVoe; after learning that DeVoe is targeting everyone who was on the bus, Ralph decides he doesn't want to be a hero anymore.
When a nuclear bomb detonates in downtown Central City, Barry, Jesse Quick and Jay Garrick slow down time by entering Flashtime.
Team Flash confronts a meta who has the ability to swap people's DNA; Barry's speed is accidentally given to Iris; Barry must act as the team leader, and Iris takes on the mantle of superhero speedster to defeat the new foe.
Barry and Ralph take different approaches to finding the remaining metas before DeVoe gets to them; Ralph's cavalier attitude frustrates Barry and the two clash over what it means to be a hero; Breacher returns to ask Cisco for a favor.
Barry and the team find a way into the Thinker's lair; Ralph considers crossing a dangerous line to defeat him; Joe is concerned by Harry's recent behavior.
When Barry needs help transporting a dangerous meta, he calls on a new friend named Leo Snart for help; Cisco becomes suspicious of Harry.
Barry teams up with Gypsy to thwart the Thinker's plan; Cisco and Gypsy discuss their relationship.
The Flash and his team put their faith in an unlikely ally, Amunet Black, to defeat DeVoe; Harry hits an all-time low when the "Council of Wells" kicks him out but then Cisco introduces him to the "Council of Harrisons."
DeVoe assaults an A.R.G.U.S. facility to complete his Enlightenment Machine; Barry realizes the only way to stop DeVoe is to allow his friends to help; Barry is reluctant to risk his friends' lives and considers taking on DeVoe solo.