Warlock Moon (1973)

Young lovers John and Jenny decide to go for a drive in the countryside one day when they happen upon the remains of a long-abandoned resort spa. After doing some exploring, they find that an elderly couple is still living in the crumbling building. They tell the youngsters that the resort was shut down long ago because it was the headquarters of a Satanic cult that performed cannibalistic rituals on unsuspecting visitors, and then invite the pair to stay for dinner. Will John or Jenny make it back to civilization alive? Will anyone believe their story?