Although the opera shares the basic characters and outline, it has a number of differences from the original story in terms of plot and emphasis. One example is in the convoy after Katerina gives Sergei her stockings: in the opera, all the women mock Katerina, whereas in the story, Sergei and Sonya mock her while Fiona and Gordyushka shame them in response to their cruelty toward her.
The Ismailov family is introduced: Boris, the father of Zinovy, the husband of Katerina for the past five years. Boris and Zinovy are merchants, ruling an estate with many peasant-slaves. Katerina is bored in their empty home, and tired of Boris' constant orders and scolding of her for not producing any children. She would actually welcome a child, and Zinovy's previous wife of twenty years fared no better.