Ten minutes after the Duc de Saligny entered the card room, the police burst in - and found he had been murdered. Both doors to the card room had been watched yet the murderer had gone in and out without being seen by anyone . '

A witches' brew ... in a castle on the Rhine. Three inexplicable murders lead world-famous sleuth Bencolin into a strange case of twisted revenge. It was a case complicated by ghosts, old legends, werewolves, magic ... and by a fascinating list of suspects: a mad duchess, an actor with a Hamlet complex, a virtuoso who likes to play his violin in the dark, a glamorous young lady who paints in the modern manner, a dynamic Belgian financier and his beautiful, weak-willed wife, and a newspaperman whose job is to report on Europe's haunted castles. Here is a sizzling witches' brew of murder and mayhem, seasoned with the typical Carr wit, and served up in an eerie Gothic setting.

It started when El Moulk's automobile roared crazily through a London fog, its driver dead as a herring. The car screeched to a stop in front of that creaky relic of ancient horrors, the Brimstone Club. Through its cavernous rooms and gaslit passages a murderer hunted victims for a private gallows. The calling cards of a notorious hangman, a miniature gibbet, a length of rope, and an inscription from the tomb of Egyptian kings warned El Moulk and his dazzling French mistress that death was on their trail. It was a perfect case for Bencolin, a detective who preferred fantastic murders.

Monsieur Bencolin investigates a series of baffling murders involving a gloomy wax museum and the mysterious Silver Key Club

Henri Bencolin, a French detective, comes out of retirement to help solve the strange murder of a Parisian courtesan, who may have been killed with one of four weapons found on the scene