The Case of the Locked Apartment

Who is the man involved in the woman's accidental death? And how did he escape the locked, guarded room? The police detective on the case believes that, no matter how improbable it seems, it had to be suicide. Etta---pseudonym Henri Derringer---agrees. But her young friend, Ceal, doesn't believe her good friend did herself in. When another death takes place, the police detective believes Ceal. Then, when Etta apparently was the target of an arrow-shot, even she began to believe Ceal. Soon, it became apparent that the guilty party was a very dangerous threat. It took all Henri Derringer's talent to uncover the whole plot.