Here is the episode synopsis:
“Kara (Melissa Benoist) deals with the loss of Mon-El (Chris Wood) by focusing all her energy on being Supergirl and the mysterious new threat against National City. Alex (Chyler Leigh) confesses a secret to Maggie (guest star Floriana Lima) about their impending nuptials. A citizen of National City has a mysterious connection to Kara, and Lena (Katie McGrath) makes a bold move.”
Supergirl Season 3 premiers Monday, October 9th at 9pm ET on The CW.
Supergirl Season 3 synopsis:
Supergirl is an action-adventure drama based on the DC character Kara Zor-El, (Melissa Benoist) Superman’s (Kal-El) cousin who, after 12 years of keeping her powers a secret on Earth, decides to finally embrace her superhuman abilities and be the hero she was always meant to be. Twelve-year-old Kara escaped the doomed planet Krypton with her parents’ help at the same time as the infant Kal-El. Protected and raised on Earth by her foster family, the Danvers, Kara grew up in the shadow of her foster sister, Alex (Chyler Leigh), and learned to conceal the phenomenal powers she shares with her famous cousin in order to keep her identity a secret. Years later, Kara was living in National City and still concealing her powers, when a plane crash threatened Alex’s life and Kara took to the sky to save her. Now, Kara balances her work as a reporter for CatCo Worldwide Media with her work for the Department of Extra-Normal Operations (DEO), a super-secret government organization whose mission is to keep National City – and the Earth – safe from sinister threats. At the DEO, Kara works for J’onn J’onzz (David Harewood), the Martian Manhunter, and alongside her sister, Alex, and best friend, Winn Schott (Jeremy Jordan). Also in Kara’s life are media mogul Cat Grant (Calista Flockhart), James Olsen (Mehcad Brooks), a photo journalist who moonlights as Guardian, a masked vigilante, Lena Luthor (Katie McGrath), and Mon-El of Daxam (Chris Wood), whose planet was ravaged by Krypton’s destruction. As Kara struggles to navigate her relationships and her burgeoning life as a reporter, her heart soars as she takes to the skies as Supergirl to fight crime. Based on characters created by Jerry Siegel and Joe Shuster, Supergirl is from Berlanti Productions in association with Warner Bros. Television, with executive producers Greg Berlanti (“The Flash,” “Arrow”), Andrew Kreisberg (“The Flash,” “Arrow”), Sarah Schechter (“Arrow,” “The Flash”), Robert Rovner (“Private Practice,” “Dallas”) and Jessica Queller (“Gilmore Girls,” “Gossip Girl,” “Felicity”).