Who is the fastest person alive? Okay, it's The Flash, but still...
The official plot synopsis for "Worlds Finest," the upcoming episode of Supergirl featuring Grant Gustin as The Flash, has been released by CBS. It confirms that the two DC Comics superheroes are indeed from separate fictional TV universes and will face off against the Supergirl villains Silver Banshee (Italia Ricci) and Livewire (Brit Morgan). Here's the synopsis...
“Worlds Finest” – Kara gains a new ally when the lightning-fast superhero The Flash (Grant Gustin) suddenly appears from an alternate universe and helps Kara battle Siobhan, aka Silver Banshee, and Livewire in exchange for her help in finding a way to return him home, on SUPERGIRL, Monday, March 28 (8:00-9:00 PM) on the CBS Television Network. Grant Gustin crosses over as The Flash.
In addition, CBS also released a new piece of promo art for the episode, an homage of the cover to Superman (vol.1) #199 from 1967 by Carmine Infantino and Murphy Anderson, featuring "Superman's Race with the Flash!"
In the actual story by Jim Shooter and Curt Swan, Superman and The Flash agree to a race around the world to benefit the United Nations. However, two rival gambling syndicates set traps for the hero they have individually bet against.
There is no indication so far that a Supergirl/Flash race will take place in "Worlds Finest."
Supergirl airs Mondays at 8 p.m. EST on CBS, with "Worlds Finest" scheduled for March 28th.