'Monster-in-Law' is a broad romantic comedy that marked Jane Fonda's return to film after a long absence, casting her as a fired news anchor who wages psychological war on her son's fiancee, played by Jennifer Lopez. The plot is a one-note battle of escalating sabotage between prospective mother- and daughter-in-law. Fonda clearly relishes the camp, but the material is thin and formulaic. A modest box-office success, it drew weak reviews and stands as lightweight, disposable star-driven entertainment.