In New York, Adele Tasca (Sophia Loren) is present when her husband is murdered by a letter bomb. She suspects the reclusive billionaire Karl Stegner (George Touliatos), his former employer, of committing the assassination. She learns that her husband, who worked as a chemist, discovered that his employer had made a contaminated drug that resulted in patients contracting cancer. The US government would like to be able to find and bring charges against this mysterious Stegner, who hides his face from the world and his income from the tax department.