Supergirl S1E18 · Worlds Finest

Supergirl

Season 1 · Episode 18 · Worlds Finest · 43 min

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.