A captain, a well-known flying ace, is developing his own device which will make a notable contribution to the prestige of his country's air force. One evening he occasionally meets a girl who strikes him with her mysterious behavior. In fact, he witnesses some completely inexplicable events that disturb him and take away the necessary serenity of mind to attend to his work, from which he feels detached. An explosion in the laboratory brings to the attention of an entire espionage network that was working to prevent the realization of the project.

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.