One night Lorna hears screams for help coming from the staircase outside her apartment. She opens her door to find a girl, who has apparently been beaten, and a man.The girl claims the man tried to rape her. The man, however, claims that the girl possesses a knife which she uses to mug old people. What should Lorna do? She lets the girl into her apartment and notices that she does indeed have a knife. A game of cat-and-mouse ensues, and, before long, one of them is caught in a trap.