About Supergirl Season 3, Episode 1 : Girl of Steel

Kara deals with the loss of Mon-El by focusing all her energy on being Supergirl and the mysterious new threat against National City. Alex confesses a secret to Maggie about their impending nuptials. A citizen of National City has a mysterious connection to Kara, and Lena makes a bold move. Guest Stars: Floriana Lima, Calista Flockhart, Adrian Pasdar, David St. Louis, Jeremy Burtenshaw, Jesse Chongo, Carlen Escarraga, Gelsea Mae, Marc Senior, Emma Tremblay, Fred Henderson, Erica Durance, Sonia Sunger, Josh Hallem,