The DEO captures a second Worldkiller, Purity. Supergirl and Alex use very different methods of interrogation with Purity in the hopes of finding out how to defeat Reign. However, Purity…

Martin and Ronnie are separated, only to realize that they must learn how to rejoin before Eiling hunts them down and kills them… and the Flash. Meanwhile, Joe shows Barry…

While Barry, Harrison, and Caitlin hunt down Ronnie, who has attacked a man, Joe recruits Cisco to help him learn the truth about who murdered Nora Allen.