Kara gains a new ally when the lightning-fast superhero The Flash 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.
|Title||Supergirl - Season 1 Episode 18 : Worlds Finest|
|Genres||Action, Adventure, Drama, Science Fiction|
|Air Date||Jan 01, 1970|
|Total Episode(s) on All Seasons||103|
|Networks||CBS, The CW|