Sir Karell Borotyn appears to have been killed by Count Mora, a vampire who prowled around his castle. One year later, Irena, Karell’s daughter, is haunted by the vampire and will be his next victim… unless Professor Zelen can avoid it.

After a four year absence, detective Nick Charles returns to New York with his wife Nora and their dog Asta. He’s approached by a woman whose inventor father is suspected of murdering her step-mother. Nick isn’t all that keen on resuming his former profession but is egged-on and assisted by Nora.