I'm working on the basic idea of my second book in a series about a female protagonist. The background is that in the first book she went from being somewhat weak and having no direction to finding personal strength and (violently) killed several people that were out to murder her. She has moved away and is now working as a flagger (one of those people who hold the sign at construction sites), trying to live in anonymity and figuring out what she wants to do with the rest of her life. While working one day, she sees a young woman in a car with a man. The girl is visibly terrified. The MC does nothing at the time (not much she can do) but later crosses paths with the girl in a public setting and I imagine a scene where the two women meet in the ladies' room and the MC moves to rescue the other girl from her predicament with the man in the car. What I can't seem to figure out is the relationship between the girl and the man and what kind of villain the guy is. The man will later murder the girl setting off a chain of events with the MC, so the pair cannot be a normal married couple; the girl would have to be someone who could disappear with little notice. Things I've ruled out as too cliche: The guy is a pimp and/or a mobster The guy is a politician (this would conflict with my last book) The girl is a prostitute The villain will try to kill the MC also, as she will know he murdered the girl when that happens. The two females will spend time together hiding from the man until the girl is killed. There will also be a police detective involved in all of this, trying to figure out what is going on between the MC and the male killer. I have not yet decided when to bring him into the story. He will be a romantic interest for the MC which will create additional conflict, but this is probably irrelevant to my dilemma. Setting is current. Location is somewhere in the middle-Atlantic states, though I haven't settled on where. I dislike the idea of this taking place in a big city (the MC would probably not live in one). I need the "man" to be a bad guy who kills easily. His background story is the biggest stumbling block; I think if I can figure that out, placing the "girl" character will be simpler. Who is the girl, and why is she with this guy in the first place? What is keeping her from fleeing on her own?