A young man, Paul Carlson, is on a trip and spends the night at count Dracula's castle. Needless to say, he is murdered. After some time has passed, the young man's brother Simon comes to the small town where all the traces end to look for him.
James Rolfe at Cinemassacre did comprehensive reviews of all of the Hammer series, and in his reviews of the Dracula movies, he went on a length about how many leads named Paul there were.