It's a year since Eugenia Ridolfi, heiress of a ruined family, has begun meeting Fulgentius, young and rich middle-class man.
For example, Eugenia does not bear Fulgentius to frequent his sister-in-law Clorinda, though he's obliged to(his brother has left for Genoa due to his job, and he must stay with her until the man is back).
Lunch takes place dramatically (according to the servants Lisetta and Tognino, which peek from the lock) and shortly after the nth argument, Eugenia and Fulgentius break up - this time forever.
The girl, to pique and revenge, accepts a proposal from Roberto: Fabrizio, who had also liked Fulgentius, now that the niece is engaged with a nobleman, forbids her to love and attend him again.
Eugenia, desperate, is forced to tell Fulgentius that she is now engaged: in the face of right accusations received from her ex-boyfriend, experiencing the blow, she faints.