Supergirl 3×23 Extended Promo “Battles Lost and Won” Season 3 Episode 23 Extended Promo Finale

Supergirl 3×23 “Battles Lost and Won” Season 3 Episode 23 Extended Promo (Season Finale) – SHOCKING SEASON FINALE – Supergirl (Melissa Benoist) and team take on Serena in an epic battle for Earth. Jesse Warn directed the episode written by Robert Rovner & Jessica Queller (#323). Original airdate 6/18/2018.