Before Supergirl helps defend the Arrowverse from an extraterrestrial invasion, she'll embark on a rescue mission of a fellow alien. The November 21 of "Supergirl" finds Mon-El held captive by CADMUS, the shady government organization run by Lilian Luthor (Brenda Strong), a surname known well to the surviving members of the House of El. False accusations will test super friends, while Alex works on being regular friends with Maggie.
It seems several members of Team Supergirl are having a bad week in aptly named episode; "The Darkest Places." Mon-El finds himself a prisoner, being captured by CADMUS at the end of the last episode. After learning this, Supergirl takes it upon herself to save the Daxomite. CADMUS though is no sucker, after the shocking revelation that The Doctor is actually the mother of Lex and Lena Luthor (Katie McGrath). Since the Luthor's have done this dance before, they've prepared themselves for a visit from any super guest, with one of their own - Cyborg Superman. His identity has yet to be revealed, but recent teasers have upped the speculation that the real Hank Henshaw might not be as dead as everyone thought.
National City's newest hero, The Guardian (Mechad Brooks) finds himself in hot water after being accused of murder. As the police hunt for the man behind the mask, James Olsen, and his partner in fighting crime, Winn (Jeremy Jordan), will have to put their heads together to clear their names and keep themselves out of jail. Meanwhile, Alex (Chyler Leigh) will continue to adapt to her new reality, including learning how to deal with Maggie (Floriana Lima) after last week's rejection.
Airing Mondays at 8 p.m. ET/PT on The CW, “Supergirl” stars Melissa Benoist in the title role, David Harewood as Hank Henshaw, Mehcad Brooks as Jimmy Olsen, Chyler Leigh as Alex Danvers and Jeremy Jordan as Winn Schott. The series also features guest appearances by Chris Wood as Mon-El, Floriana Lima as Det. Maggie Sawyer and Tyler Hoechlin as Superman.