"Menaces" deals with the months before WW2 in a hotel :t he fear of the impending war never leaves the guests of an hotel in Paris.
Mathilde Strangerson, the daughter of an eminent scientist, narrowly escapes being murdered in her own bedroom by an unknown assailant. As the room was locked from the inside, no one can understand how the attacker managed to enter or leave the room. Reporter and amateur sleuth Joseph Rouletabille arrives on the scene to protect Mathilde and resolve the mystery of the yellow room.
Nadia de Hock breaks her engagement to another man because of her love to the marquis d'Areghi. She lives a life of pleasure until Areghi reveals he is just an adventurer who has just killed his brother. He asks her to sign a letter so he can use her as his alibi. Some time later, Areghi is attacked by Nadia's guard dogs as he tries to see her. He dies as she forgives him for the pain he caused her.
