S4, E15: Secretly furloughed from prison due to failing health, Lex Luthor (special guest star JON CRYER) visits his sister, Lena, to seek her help finding a cure. Savvy as ever, Lena is suspicious of Lex's motives, but when she's faced with a life and death situation, she must decide how she truly feels about her brother. Meanwhile, Supergirl and J'onn face off against Manchester Black. James's sister Kelly (guest star AZIE TESFAI) comes to town.