"Worlds Finest" -- Kara (Melissa Benoist, left) gains a new ally when the lightning-fast superhero The Flash (Grant Gustin, right) 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 28 (8:00-9:00 PM, ET/PT) on the CBS Television Network. Also pictured: Mehcad Brooks (center) Photo: Michael Yarish/Warner Bros. Entertainment Inc. ÃÂ© 2016 WBEI. All rights reserved. | Episode 1.18 - Worlds Finest | Promotional Episode Photos | Season 1 | Supergirl | Gallery

SpoilerTV Image Archive | Gallery | Supergirl | Season 1 | Promotional Episode Photos | Episode 1.18 - Worlds Finest | "Worlds Finest" -- Kara (Melissa Benoist, left) gains a new ally when the lightning-fast superhero The Flash (Grant Gustin, right) 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 28 (8:00-9:00 PM, ET/PT) on the CBS Television Network. Also pictured: Mehcad Brooks (center) Photo: Michael Yarish/Warner Bros. Entertainment Inc. ÃÂ© 2016 WBEI. All rights reserved.

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