House of Dark Shadows (1970) on Netflix

Barnabas Collins is unleashed from his long captivity by greedy Willie Loomis who had hoped to find the missing Collins family jewels, but instead found the family's darkest secret. Soon, women are being attacked and suffering blood loss. Meanwhile, the Collins family welcomes their newly discovered "cousin from England", not suspecting his terrible secret--he's a vampire. Dr. Julia Hoffman, a blood specialist, learns the truth and offers Barnabas Collins the chance of a cure for his affliction. But as Barnabas begins a relationship with Collinwood governess Maggie Evans, seeking in her his lost love Josette du Prés, complications arise and the stage is set for betrayal and death.