Like The Mystery of the Yellow Room, The Secret of the Night is a Joseph Rouletabille mystery. The main character, detective Joseph Rouletabille must once again face a new riddle and solve it. This time it will be harder. In this case he is brought to Russia by the Czar to protect General Trebassof, whose assassination has been plotted by the revolutionariesthe Nihilists. The author again keeps all readers in tension to the end.