The narrative begins on a dark September night when Humphrey Jardine, a medical student living near Hampstead, discovers the body of an elderly clergyman in Millfield Lane. When he returns with the police moments later, the corpse has completely vanished. The police grow suspicious of his story, especially when subsequent investigations reveal no traces, save for a blood-stained fence and an enigmatic gold reliquary bearing clerical initials. Jardine's life takes a darker turn when he takes up a brief locum tenens in Camden Town.
There, he encounters the enigmatic Mrs. Samway and narrowly escapes death after being lured into a sealed mineral water cellar and subjected to a lethal chamber of carbon dioxide. Amidst these chilling attempts on his life, renowned medical jurist Dr.
John Thorndyke steps in. Using rigorous scientific methods, microscopic evidence, and logical deduction, Thorndyke begins to peel back the layers of deception surrounding the missing body, the cremated remains of a patient named Septimus Maddock, and the invisible enemy who haunts Jardine's footsteps. The story culminates in a tense struggle against a relentless adversary, weaving a complex web of art, forgery, and hidden motives against the rustic backdrop of Hampstead Heath.
