There are a number of inheritors to a fortune who are getting killed by a mysterious somebody whom we do not see. Each death is novel, but not terribly graphic. Who did it?

A penniless countess falls in love with a cad, unaware that he is also involved on the side with her beautiful daughter.

La Cittadella is a 1964 Italian miniseries based on A. J. Cronin's 1937 novel, The Citadel, and produced by Radiotelevisione Italiana. It was directed by Anton Giulio Majano and stars Alberto Lupo as Dr. Manson and Anna Maria Guarnieri as his wife, Christine. Other television versions include an American, another Italian, and two British adaptations.