Leaving the chapel in London's 19th century Thames' side where she teaches the alphabet to a raggle-taggle of urchins, Mariah Fox is charged by a stray pig. The quick intervention of Tobias Longreach saves her from certain injury. Mariah has always believed her destiny to be teaching. After the early death of her mother, she was brought up by her papa, Jerome, to believe that she could learn anything a boy could. She shares his vision of a future in which everyone, rich or poor, boy or girl, will be taught at least the rudiments of reading, writing, and counting.

Tobias was brought up a second son, but following his elder brother's premature death, inherits an Earldom and the need to provide it with an heir. He comes to believe that Mariah will make a perfect countess and enrolls her papa's help in securing her hand.

However, Sir Lucas Wellwood, whose debts have made him urge his sister to attempt to trap Tobias into marriage, has sinister intentions. Mariah suspects Wellwood has been mistreating his sister and she heads off impetuously to rescue her. Will Tobias and his friends reach Wellwood's home before he can exact revenge on Mariah?