Sherlock Holmes and the Secret Weapon

Holmes is called into the Inner Council of British Intelligence by Sir Evan Barham to assist in stopping Nazi saboteurs. The demand signals the start of a tense, high-stakes investigation.

Gavin, one of Holmes's operatives, is killed by a German dagger in his back. As he dies, he mutters the name "Christopher," hinting at a clue to the case.

Holmes and Watson travel to Limehouse in London to meet Gavin's wife Kitty. They seek information about the Voice of Terror and honor Gavin's memory.

Holmes uses oscilloscope analysis to compare radio voice patterns, proving The Voice of Terror is recorded on phonograph records in the UK but broadcast from Germany. The discovery points to a hidden conspiracy at home.

Kitty provides a tip guiding Holmes to pursue the trail at the old Christopher Docks. Holmes, Watson, and Sir Anthony Lloyd encounter Meade and Nazi spies and are captured, then freed by East End men.

During the arrest, Meade escapes through a trap door to a waiting speedboat, slipping out of Holmes's reach. Holmes and Lloyd regroup after the escape.

Kitty disguises herself as a thief to join Meade's circle, learning that he plans to travel to Sir Evan's Kent estate that night. Her ruse keeps her close as the trap tightens around the conspirators.

Holmes and Sir Evan watch a German plane land; Meade passes a package to the pilot and disappears. The scene suggests Meade's plan is moving toward Sir Evan's Kent estate.

An informant tracks Meade and Kitty to the south coast of England. Holmes insists the council accompanies him to confront the spies by the shoreline.

Holmes and troops capture Meade and a group of German soldiers in an abandoned church. The operation exposes the network and secures the area against further sabotage.

Holmes reveals that The Voice of Terror is Sir Evan Barham, an impostor who is actually Heinrich Von Bock in disguise. He explains the World War I background, the resemblance to Barham, and the plastic surgery used to maintain the deception.

Holmes informs the spies that the German invasion force has been destroyed. The sabotage plot is thwarted and the threat to Britain is averted.

Meade fatally wounds Kitty as he attempts to escape, delivering a fatal blow in a bitter betrayal. The conspirators' plot suffers a major setback as Kitty succumbs.

Meade is killed while trying to escape after shooting Kitty, ending the immediate threat. His death marks the collapse of the Nazi operation on the coast.

The Council stands around Kitty's body and swears that her heroic death will not be in vain. Holmes and his team honor her memory and vow to continue the fight against the Nazi threat.