An armored alien with advanced tech is hunting down the Fort Rozz prisoners... and executing them. While Supergirl tries to find him, James questions whether the DEO has the right to lock up Max without charges or a trial. Meanwhile, Kara tries to deal with Cat's new assistant at work, who is intent on upstaging Kara.

After defending Supergirl to the public, Cat is forced to issue a public warning after exposure to Red Kryptonite turns Supergirl into a power-mad villain.