La duda (1972)

After learning of the death of his son, don Rodrigo, a count who emigrated to America long time ago, returns to Spain old and ruined. The one that once was his mansion, now belongs to his ex-daughter-in-law Lucrecia. However, knowing that she committed adultery, the doubt that obsesses the old count is to find out which of her two granddaughters is the legitimate one.