The assistant stage manager of a small-time theatrical company is forced to understudy for the leading lady at a matinée performance at which an illustrious Hollywood director is in the audience scouting for actors to be in his latest "all-talking, all-dancing, all-singing" extravaganza.

In 1830, the Karnstein heirs use the blood of an innocent to bring forth the evil that is the beautiful Mircalla - or as she was in 1710, Carmilla. The nearby Finishing School offers rich pickings not only in in the blood of nubile young ladies but also with the headmaster who is desperate to become Mircalla's disciple, and the equally besotted and even more foolish author Richard Lestrange.