Alright you comic geeks, who is faster? The Flash ? Supergirl? CBS wasted no time in promoting its upcoming cross over of The Flash on Supergirl episode promotion with a twitter teaser below. Episode 18 titled World Finest had The Flash trapped in an alternate time line at National City. He needs Supergirl help to find his way home. But not before he help Supergirl take down Silver Banshee and Livewire. The cross over episode will air on March 28th. If you can’t decide who is faster, check out an old animation clip when The Flash and Superman too trying to figure out who is faster between the two.
— Supergirl (@TheCWSupergirl) March 17, 2016