Serena is a devoted wife and mother, content in her quiet domestic life. But her ambitious husband betrays her for a wealthy heiress, carrying on a secret affair. When childhood friend Matteo reappears and offers his love, Serena refuses, clinging to her marriage vows. However, the mistress refuses to be a stepmother and pressures her lover to get rid of his family. Blinded by ambition, he and his mistress push little Leo from the balcony of their high-rise apartment. Serena rushes home and witnesses the unthinkable. Shattered and enraged, she vows vengeance. The gentle wife is gone—a formidable enemy has been born.