Catherine, the godmother of the Mafia, tracks down her long-lost twin sister at last, only to discover her sister is already suffering from terminal cancer. On her deathbed, the sister pleads with Catherine to raise and properly educate her three children. Catherine poses as her late sister and returns to the family home, where she soon uncovers a harsh truth: her sister's husband never truly loved his wife. He has been cheating on her for years and has even moved his mistress into their house. While nurturing the three children into accomplished, well-educated adults, Catherine accidentally stumbles upon the real cause of her sister's death—her sister was deliberately poisoned by her own husband and his mistress. As the formidable Mafia godmother, Catherine will make this despicable couple pay dearly. Nobody hurts her sister and gets away with it.