Denis, a poor student in philosophy, works as a night porter in the Paris market of Les Halles in order to pay for his studies. Constantly weary, he falls asleep and dreams of a beautiful girl in white, Irène, with whom he falls in love.

Paris is prey to an invisible terror against which the police can do nothing: a sinister organization that sows chaos and death. The intrepid journalist Philippe Guérande and his partner embark on a long crusade to put an end to the crimes of the Great Vampire and Irma Vep, his dangerous accomplice. (A ten episode movie serial.)