As soon as Katerina's father arrives at her and Danilo's home the next morning, he demands that she explain her late return the previous night. In the ensuing fight, Katerina's father shoots Danilo in the arm before she intervenes and begs them to forgive one another.
The passage describes a conflict between Katerina and her father, where Katerina's father is angry about her late return and ends up shooting Danilo in the process of an argument.  Katerina then steps in to stop the fight and ask for forgiveness.