House of Dark Shadows is a 1970 featurelength horror film directed by Dan Curtis, based on his Dark Shadows television series. Filming took place at Lyndhurst Estate in Tarrytown, New York, with additional footage at nearby Sleepy Hollow Cemetery. In this film expansion, vampire Barnabas Collins Jonathan Frid searches for a cure for vampirism so he can marry a woman who resembles his longlost fiance Josette Kathryn Leigh Scott. Curtis followed this movie one year later with Night of Dark Shadows, another expansion of the Shadows franchise, dealing with the witch Angelique Bouchard Collins.
Barnabas introduces himself to the family under the guise of a cousin from England. Elizabeth and the others are intrigued by Barnabas and take an instant liking to him. Barnabas insists on moving into the Old House and hosting a ball in honour of the family however, on the night of the ball, Elizabeths daughter Carolyn Stoddard is bitten by Barnabas while she is getting ready.Later on at the ball, he is introduced to young David Collinss governess and Jeffs girlfriend Maggie Evans and is instantly smitten with her, as she bears a striking resemblance to his longlost fiance, Josette du Pres. Maggie is thinking about leaving Collinwood, but Barnabas persuades her to stay. Back at the Old House, he tells Willie about Josette and how she took her own life on the night they were to be married. Carolyn overhears and threatens to expose him out of jealousy. Enraged, Barnabas delivers a deadly bite to Carolyn, much to Willies horror. A shaken Willie takes Carolyn back home she slowly walks to the doorway, but she is soon discovered slumped in the doorwaydeadby the maid, Mrs. Johnson. ........
Source: Wikipedia