Contains spoilers for "Supergirl" Critics didn't hold back in their negative reviews for "Supergirl." But one sequence that is a highlight is the flashback to Kara's (Milly Alcock) time in Argo City, the last vestige of Krypton after its destruction. Kara was born in a world already on the decline, and despite her father saving the city, everyone starts getting sick and dying due to exposure to kryptonite from within the now-exposed planet.