A young Harvard graduate serves as confidential secretary to an elderly multi‑millionaire philanthropist and notices troubling oddities after an evening visit; discovering his employer's practice of keeping charitable funds in a strong vault, he adopts a protective, investigative role and pursues fraudulent appeals. His inquiries draw him into the city's criminal underworld, where he uses aliases, follows second‑hand dealers, deciphers a cipher message, confronts robbery and false alibis, fights to stay ahead of conspirators, and races against time toward a final confrontation in an old warehouse that exposes the scheme against his employer.