After Mike saves Leda Mills from three would-be rapists, she decides that the only way she can regain control of her life and prevent her attackers from hurting other women is to hunt them down and murder them; Marcellus helps a teenager being neglected and corrupted by his drug-addicted father; Mike is horrified when Leda phones him after the first murder to thank him for being her inspiration, and works with Marcellus to stop her killing spree, but it's Liz's insights into her behavior that give them the key to her capture.