In 19th century Serbia, the town of Schettel is cut off from the rest of the world by the plague. The local doctor (Richard Owens) tries to procure some medicine from the outside world, along with his son Anton (John Moulder-Brown).
Upon his return to Schettel, Anton finds a circus – the “Circus of Nights” – has been set up there with a Gypsy woman (Adrienne Corri), a clown-faced dwarf (Skip Martin), a strongman (David Prowse), twin acrobats (Robin Sachs and Lalla Ward) and various others in tow.
Shortly afterwards people in the town begin to die mysteriously, their bodies drained of blood.
It transpires that the ‘circus’ is populated by vampires able to change into animals at will, and is run by Emil (Anthony Corlan), a cousin of the notorious Count Mitterhouse (Robert Tayman), killed by a stake through his heart some fifteen years earlier.