Renzo and Lucia's love story is jeopardized by Don Rodrigo, a wicked nobleman, who is interested in Lucia. When she refuses his attentions he has her kidnapped and brought to a convent whose prioress is a nun as wicked as he is. The two youths will have to go through a lot of misfortunes before being reunited and being able to marry.

Il film ripercorre fedelmente le pagine del grande romanzo di Alessandro Manzoni, cominciando con l'intimazione dei bravi a don Abbondio di non celebrare il fatidico matrimonio. Continuando poi con la fuga dal paese, la conversione dell'Innominato, la rivolta, la peste e, quindi, le nozze.