Professor Karas is widely known as enthusiastic propagator of the motto "Morality Above All Else". He guides his students as well as his own family to live a morally decent life. One day he has an unexpected visit. It's his illegitimate daughter Vera, who is proof of his thoughtless youth. Mr. Karas know that she can ruin his image, thus he decides to keep her a secret and asks her to leave. Instead of leaving she takes a position of a governess in his own family without letting him know. Mr. Karas realizes that he must reveal the truth sooner or later, but he doesn't have enough courage to do so. As he postpones it, he is more and more scared to come to his own home.