Supergirl - Season 2 - Eps 11: The Martian Chronicles
Armek, a White Martian, descends on National City intent on taking M’gann back to Mars to face her punishment as a traitor. Hank and Supergirl determine the best way to keep M’gann safe is to bring her to the DEO. However, when it is revealed that Armek shape-shifted into M’gann and is now loose in the building, the team realize he could be disguised as any one of them.
About Supergirl

Title: Supergirl
First Air Date: 2015-10-26
Last Air Date: 2021-11-09
Status: Ended
Rating: 7.3/10 (from 4222 votes)
Language: EN
Seasons: 6
Total Episodes: 126
Network: CBS The CW
Genres: Drama, Sci-Fi & Fantasy, Action & Adventure
Production Companies: DC Entertainment, Berlanti Productions, Warner Bros. Television
Synopsis
Twenty-four-year-old Kara Zor-El, who was taken in by the Danvers family when she was 13 after being sent away from Krypton, must learn to embrace her powers after previously hiding them. The Danvers teach her to be careful with her powers, until she has to reveal them during an unexpected disaster, setting her on her journey of heroism.
Cast

Melissa Benoist
Kara Danvers / Supergirl / Kara Zor-El

Chyler Leigh
Alex Danvers / Sentinel

David Harewood
J'onn J'onzz / Martian Manhunter

Katie McGrath
Lena Luthor

Jesse Rath
Querl 'Brainy' Dox / Brainiac-5

Nicole Maines
Nia Nal / Dreamer

Azie Tesfai
Kelly Olsen / Guardian

Julie Gonzalo
Andrea Rojas / Acrata

Staz Nair
William Dey

Peta Sergeant
Nyxlygsptlnz / 'Nyxly'