Watch Father Sergius for Free: How to Stream the Movie Online at 123Movies. . A film adaptation of the novel of the same name by Leo Tolstoy. The main character of the film is Prince Stepan Kasatsky, an officer, an ardent, proud young man — a big fan of the tsar. Kasatsky is going to marry, but at the last moment he learns from the bride that she was the mistress of the emperor. The prince is deeply disappointed in social life, he takes a monastic vow and leaves the capital. Faith in God was to save the soul, but passions and worldly temptations don't leave Kasatsky.