Supergirl and Lena go to Stryker's Island to check out Lex's cell, and find a clue to his schemes. Supergirl is declared a criminal and is forced to question whether she does more harm or good, while James deals with the fallout from being injected with the serum.
Season Number: 4
Episode Number: 18
Episode Title: Crime and Punishment
Air Date: Apr 21, 2019