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

Inspecor Lipinski investigates the theft of a 500 carat diamond.

Professor Van Dusen, the 'Thinking Machine', boasts that he can think his way out of a prison cell. When he is locked up he is given the chance to prove that he can escape by the power of his mind alone.

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

Valmont has to help break a ring of counterfeiters.

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.

In turn-of-the-century Vienna, Dagobert Trostler investigates a poison pen case.

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

William Drew of the foreign Office investigates an unusual crime.

Charles Dallas is led into a strange and sinister adventure in the aftermath of a sensational murder trial.

Gold disappears from the strongroom of the RMS Oceanic and its purser, Mr Horrocks, tries to discover what has happened.

Hagar the Gypsy sets out to prove that Detective Sergeat Grubber is wrong about who killed Mrs Arryford.