Polly Burton assists in soving the case of a grl found dead on a seat of an underground train.

Laxworthy and two friends secure the safety of the plans for the first torpedo to be used by the French navy.

Lieutenant Holst of Copenhagen has to help a Russian countess who claims her brother-in-law aims to kill her.

Professor Van Dusen must find out why a young woman had a perfectly healthy finger cut off by the eminent surgeon Prescott.

Dr Thorndyke has to decypher a code to stop a plot to assassinate a Russian Grand Duke.