"He tried to change you, Marlize. But I think that deep down, you are still an optimist. You still believe in humanity. And I believe in you. You asked me what I was willing to do for my husband. And now I'm gonna ask you... what are you willing to do for the world?"
Iris West convincing Marlize DeVoe to help Team Flash
"Think Fast" is the twenty-second episode of the fourth season of The Flash, and the ninety-first episode overall. It aired on 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.[1]




  • When DeVoe is attacking A.R.G.U.S., he plays and moves to part 2 of the Messiah Highlights.
  • Diggle's extreme susceptibility to motion sickness is once again witnessed, with Iris, Caitlin and Cisco preparing a trash can and water bottle for his inevitable bout of vomiting following Barry superspeeding him into S.T.A.R. Labs.
  • Cisco likens DeVoe to the Legion of Doom, suggesting they send the "Super Friends" to defeat him. The "Super Friends" typically refers to the Justice League of America, the name originating from the TV series of the same name. In that series, the Legion of Doom were also an enemy of the Super Friends.
  • When the delivery guy brings Joe and Cecille's food, he goes to compliment the house. Joe suggests the phrase "bitchin'", yet another callback to the season premiere in which the team decodes a message from an entranced Barry says "this house is bitchin'".
  • This is the second episode of the Arrowverse to feature John Diggle without Oliver Queen, the first being "King Shark".


  1. Flash Spoilers: “Think Fast” with David Ramsey - FlashTVNews
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