Mild-mannered doctor Ralph Morgan and his fiancee Maxine Doyle seem like your average early 20th Century Middle-European couple...but the doctor's hunchbacked servant Mischa Auer is a tipoff that this is a horror movie of some sort. Like many men, the doctor has suffered from a vampire curse all his life. And, like many men, he is unaware of his blood-sucking habit, thanks to the concealment efforts of his loyal (hunchback) servant. Doyle discovers her fiance's sanguine secret, but not before she finds out she really loves Gleason, anyway. Answers the question: just how do you jilt a vampire?