During the Mad Hatter Masquerade, a fundraiser hosted by the Friends of the Opera on the grounds of the old Pendleton Grist Mill, Harlan Sadler, husband of Cricket Sadler, the chairwoman, is killed. He´s been hit in the head with a croquet mallet, and his body hung on the chains and paddles of the grist mill. Nobody can figure out why since Harlan was much beloved by everyone. It´s only after Cricket and Delaine beg Theodosia to investigate that she realizes the killer might have mistaken Harlan for his crazy son, Duke. After all, Duke is a slum landlord and recently injured a woman in a boating accident.