No way in and now way out, how did the vicious attack on Ms Stangerson's occur? How did the attacker get in and out of the room? And how can Joseph Rouletabille protect her from further attempts on her life if the attacker seems to defy the laws of physics? Can you solve the impossible crime? Leroux's 1907 masterpiece is still considered one of the all time greatest ‘locked-door’ mysteries.