Supergirl 1x18 Sneak Peek #4 “Worlds Finest“ (HD) The Flash Crossover

Supergirl 1x18 “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 28th on CBS. Grant Gustin crosses over as The Flash. Subscribe to tvpromosdb on Youtube for more Supergirl season 1 promos in HD! Official website: Official Twitte