Vampire hunter Professor Abronsius (Jack MacGowran) and his faithful assistant, Alfred (Roman Polanski), are traveling across Transylvania when they stop to rest at a suspicious-looking inn. That night, they witness the innkeeper's daughter, Sarah (Sharon Tate), being whisked away by Count von Krolock (Ferdy Mayne), an obvious vampire, and pursue him to his nearby castle. They break in, only to be invited to stay by the unfazed count, and plot to rescue Sarah and destroy their murderous host.