Jane Kanwhistle leaves ten thousand pounds from her estate to her nephew, Frederick Corder--provided that he commit a different crime each and every day for a year, and avoid prosecution and imprisonment. Fred and his writer wife Adeline decide to carry out the terms. But when their cousin Percy, Kanwhistle's primary heir, is murdered, Fred is accused of the crime--and only Mr. Jellipot and Inspector Combridge can find the real killer.