'The Flash' Pits John Diggle Against The Thinker in "Think Fast" Synopsis

The CW has released the official synopsis for "Think Fast," the May 15 episode of The Flash in which David Ramsey guest stars as John Diggle, his character from Arrow.

During a recent interview with EW, actor David Ramsey revealed that The Thinker will shapeshift into Diggle in an effort to penetrate the secure ARGUS facility where Team Flash is keeping Fallout in the wake of last night's episode.

"You get to see Diggle come in and tear through some ARGUS agents," Ramsey said. "It's always fun to go to Flash because Flash is all light."

Ever since Arrow killed off their version of Amanda Waller in season 4, Diggle's wife Lyla Michaels has been running ARGUS. Until recently, they had not utilized that connection as much as you might think, but part of that may have been just actor availability for Audrey Marie Anderson, who plays Lyla.

"I think not being able to get Audrey was part of it," Ramsey told ComicBook.com when we recently asked why the organization had not joined the season earlier. "I think it was strategic in bringing in ARGUS in this specific time. ARGUS has always been kind of been working in the background even when we didn't know it, much like SHIELD is always around in the Marvel universe. So it wasn't by accident that it came by and leaked part of the scene. They'll be very involved in wrapping up to our finale and into season seven. We want to make some logical use of ARGUS and also the dynamic that his wife is the director of ARGUS What does that mean? What does that mean to the Team Arrow? How can we utilize her resources? What does that mean to the relationship? So there's a lot that has to kind of play out in season seven in terms of ARGUS and Diggle's involvement. Yes, it was planned from the very beginning. "

You can check out the full synopsis below.

DAVID RAMSEY GUEST STARS

When DeVoe assaults an A.R.G.U.S. facility to complete his Enlightenment Machine, Barry (Grant Gustin) realizes the only way he can stop him is if he allows Cisco (Carlos Valdes) and Caitlin (Danielle Panabaker) 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.

Viet Nguyen directed the episode written by Sam Chalsen & Kristen Kim.

The Flash airs Tuesday nights at 8 p.m. ET/PT on The CW. "Think Fast" debuts on May 15.