Written in collaboration with Sintair (Hermann Sartini)
- See also the review at The Passing Tramp
Fog-ridden London is being terrorised by the mysterious figure of Mr. Smith, a serial killer who coshes his victims over the head and takes their wallets, leaving a calling card behind. When, one day, somebody follows Mr. Smith home, they discover his address: the murderer lives at no. 21 Russel Square! There's just a small problem... 21 Russel Square is a guest house! Before long, Mr. Smith commits another murder, this time inside his own home, and directly challenges the police to try and catch him... Can the police find Mr. Smith before he disappears into the fog?
- Was adapted into a movie by Henri-Georges Clouzot