It could be a plot for a Hollywood thriller: A kindly man takes in a business colleague as a boarder. All is well until the house guest begins spying on him in compromising positions — and is found to harbor an unwelcome infatuation.

That scenario was all too real for the plaintiff in S.Z. v. M.C., A-3841-09, a case that tests whether the Prevention of Domestic Violence Act applies to people who live in the same house but are not related by blood or by romance.