The play takes place in the 1920s at the summer home of Jack Gay and his wife, Stella. Jack and Stella are awaiting a visit from Stella's mother, Arabella Nagg, her husband Noah and Stella's sisters. In the well-worn mother-in-law/monster-in-law tradition, Arabella's arrival soon turns the home into anything but peaceful and when notes passed between characters are intercepted and the hidden baby is mistaken for a piano, the consequences become excruciatingly funny.