When William Charlmont is lost at sea, his devoted wife lies dying in childbirth, and charges Catherine, their eldest daughter, to await his return. Years later, and now in her thirties, Catherine remains faithful to her promise, resigning herself to a life of spinsterhood. Her two sisters, however, are under no such obligation, and while Lucy loves and loses from afar, the carefree Jane resolves to make a prosperous marriage and become a lady of fortune. Commonplace is a charming and witty tale of the tortuous path a girl must take to secure a suitable match.