In a small London alley, Pentecost Alley, not far from Whitechapel, the body of a strangled prostitute was found in an apartment building. In the bed of the murdered woman, a gold badge-emblem was found with the inscription “Hellfire Club”, and on its reverse side was the name of Finlay Fitzjames, the son of one of the most influential representatives of London high society. Police Superintendent Thomas Pitt immediately took up the case. Father and son Fitzjames unanimously declared that Finley was innocent, and that the evidence was planted at the crime scene by one of their many enemies. Meanwhile, the city's public is agitated - of course, because quite recently Jack the Ripper committed his terrible murders in these places, and the police never found him. Never before has Thomas Pitt had to work under such pressure...