Preston Hauser, owner of a famous department store, asks his head of
security, Quint McCauley, to investigate some threatening letters he has
received. No sooner does Quint take on the job, than Preston is poisoned
by one of his own vitamin pills. With Quint looking on. Suspicion falls
on Hauser's young wife, Diana, but Quint quickly learns she's not the
only one who might benefit from the millionaire's death.