Ms. McNulty is Tom’s neighbor, a young woman with a son named Jesse. Tom meets her after he sees a boy, whom he believes to be Jesse, pushed into the sea by a little girl and runs to her flat to alert her; however, Ms. McNulty informs him that Jesse is fine and her daughter is dead. Ms. McNulty tearfully confides in Tom that she is hiding out from her husband, who raped her daughter to death and threatened to hurt her and Jesse next. Tom vows to protect her and Jesse, and he fulfills this promise at the end of the novel, when he kills Ms. McNulty’s husband when he attempts to abduct Jesse.