We have the episode description of 18th episode of season one of Supergirl, titled Worlds Finest. This episode will be airing on Monday, March 28, 2016 at 8pm EST time. Check out the description below of this episode.
Supergirl gains a new ally when the lightning-fast superhero The Flash helps her battle Livewire and Silver Banshee.
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.