Supergirl: 2x11
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.
2 - 1The Adventures of Supergirl Oct. 10, 2016
2 - 2The Last Children of Krypton Oct. 17, 2016
2 - 3Welcome to Earth Oct. 24, 2016
2 - 4Survivors Oct. 31, 2016
2 - 5Crossfire Nov. 07, 2016
2 - 6Changing Nov. 14, 2016
2 - 7The Darkest Places Nov. 21, 2016
2 - 8Medusa (I) Nov. 28, 2016
2 - 9Supergirl Lives Jan. 23, 2017
2 - 10We Can Be Heroes Jan. 30, 2017
2 - 11The Martian Chronicles Feb. 06, 2017
2 - 12Luthors Feb. 13, 2017
2 - 13Mr. & Mrs. Mxyzptlk Feb. 20, 2017
2 - 14Homecoming Feb. 27, 2017
2 - 15Exodus Mar. 06, 2017
2 - 16Star-Crossed (I) Mar. 20, 2017
2 - 17Distant Sun Mar. 27, 2017
2 - 18Ace Reporter Apr. 24, 2017
2 - 19Alex May. 01, 2017
2 - 20City of Lost Children May. 08, 2017
2 - 21Resist May. 15, 2017
2 - 22Nevertheless, She Persisted May. 22, 2017