An ex-boxer has trained his own son and leads him on to win the middle-weight championship of Italy. But the boy falls easy prey to a woman of light morals and renounces the hard work of sport to follow her to a winter luxury resort and at a certain moment, offers to marry her but she, not wanting to give up an advantageous connection, turns him down, advising the youth to not change the nature of their relationship. Then, the boy feeling the entire baseness of his situation, returns home to his parents who welcome him back with joy and takes up again a commitment to sport.