Season 4 Episode 21TVMSHOW Not rated yet Your Rating login to see it
Kara comes face to face with Red Daughter and the two engage in an epic battle. Determined to find a way to extract the Harun-El, Lena turns to an unlikely source for help - Lillian Luthor. Meanwhile, Alex realizes she's missing parts of her memory, and Brainy, Nia and J'onn set out to track down aliens who have been abducted by Lex. The crossover continues on The Flash S03E08 Invasion! (II), Arrow S05E08 Invasion! (III) and DC's Legends of Tomorrow S02E07 Invasion! (IV).