Dr. Karl Sternau, the personal physician of the count Bismarck, who spent much of his youth in Mexico, is sent back to that country during the occupation by French troops in the service of the Austrian 'Emperor' Maximilian, to carry an encouraging letter from U.S. President Lincoln to the nationalist Mexican president Benito Juarez.

Andrea Artusi is a successful businessman with a beautiful wife, Maria, and a happy marriage - until he has an affair. After his own cheating, he starts to become obsessed with his wife's fidelity. Since she is one of the most desired women in town, he worries that it would be very easy for her to cheat on him. Now every time a man looks at his wife, Andrea goes crazy. Meanwhile, Maria finds out about her husband's affair and decides to plan her revenge.