In Victorian England, a series of mysterious explosions reveals the work of a rogue scientist testing miniature flying bombs—early drone-like weapons—on civilians. Prime Minister Benjamin Disraeli secretly assigns inventor Sidney Orebar and agents Moira Hunter and Liza Hart to investigate.

As they track the attacks, the team uncovers a hidden network of factories and learns that the scientist, Dr. Voss, is preparing to sell his deadly technology to a powerful secret society. Racing against time, they infiltrate his operation, confront him in a vast underground lab, and stop the mass deployment of his weapons—barely preventing a new era of mechanized terror.