Full Moon of the Virgins (1974)

Karl Schiller thinks that he found a magical ring that has a great power, and it's located in the Dracula's castle. His brother Franz is a gambler and he wants to get this ring. Karl gives him a special amulet which can protect Franz from the vampires. He grabs the amulet and next night goes to vampire caslte. He was met by a strange countess, who invited him to dinner. And yes, that night his brother (who is actually his twin bro) also arrived in the castle. Suddenly, the realized that this night was the "Night of the Virgin Moon", which happens very rare. Today, due to the devil's ceremony, 5 virgin girls will be brought in the castle to become the sacrifice in this evil ritual. Can brothers protect each other and rescue these poor little girls?