In Victorian-era Britain, a secret society known as the Illuminati devises a catastrophic plan to destroy England by triggering massive sea disturbances along the coast using hidden mechanical seismic engines. Their goal is to unleash a devastating tsunami that would wipe the nation from the map.

The plot is uncovered by Marion Shuster, who overhears their plans and alerts the British Secret Service. Prime Minister Benjamin Disraeli assigns top agents Sidney Orebar and Moira Hunter to investigate and stop the threat. Racing against time, they track the conspiracy to a concealed coastal installation, infiltrate it, and confront the Illuminati leadership. Through skill, courage, and quick thinking, they disable the machine just moments before activation, saving England from destruction—while hinting that the secret society may still survive.