The Ghoul Bande son (1975) BO

In the 20's, the wealthy and spoiled Daphne and Billy challenge her brother Geoffrey and his girlfriend Angela to dispute a car race to Land's End. Angela feels sick and asks Geoffrey to stop the car, but Daphne goes on to win the race. However, she is forced to stop in a fog since the car runs out of gas. Billy takes a gallon to seek out gas and Angela stays in the car waiting for him. She decides to snoop around and is kidnapped by a stranger named Tom Rawlings. Then he takes her to a manor owned by Doctor Lawrence, a lonely man that lost his beloved wife and son in India and lives with the his servant and former nanny Ayah. He invites Daphne to have a vegetarian dinner with Aya and him while Tom returns to the car where Billy is waiting for Daphne and pushes the car and Billy off a cliff. Meanwhile, there is a mysterious guest in the room in the upper level of the house. What is the secret of Dr. Lawrence and Aya?