Una serie di macabri omicidi sconvolge Londra. In ogni scena del crimine rimane solo un mucchio di ossa della vittima insieme a una bizzarra sfera coperta da strani simboli. Il figlio dell'ultima vittima chiede aiuto a Sherlock Holmes e al suo precedente partner, il Dott. John Watson. Dopo una prima indagine, la coppia di Baker Street scopre un filo conduttore che collega gli omicidi: geometrie bizzarre basate su antichi schemi permettono a creature ultraterrene di entrare nella nostra dimensione, cercando di creare caos e distruzione. Le persone responsabili stanno guadagnando talmente tanto potere che anche il più grande nemico di Holmes li teme abbastanza da cercare una diabolica alleanza.

The second novel in Lois H. Gresh's Sherlock Holmes vs. Cthulhu series. Amelia Scarcliffe's monstrous brood, harbingers of Cthulhu, will soon spawn. Her songs spell insanity, death... and illimitable wealth. And Moriarty will do anything to get his hands on gold, even if it means tearing down the walls between this world and a realm of horrors. Meanwhile, after Sherlock Holmes' last tangle with the Order of Dagon, horrifying monsters haunt the Thames, and madness stalks the streets of Whitechapel. Gang war between Moriarty's thugs and the powerful cult can only bring more terror—unless Holmes and Dr. Watson can prevent it. But can they find the cause of the neural psychoses before Watson himself succumbs?

The third novel in Lois H. Gresh's Sherlock Holmes vs. Cthulhu series. Now united, both Fitzgerald and Moriarty travel to Innsmouth, the stronghold of the cult of the Old Ones. Holmes and Watson, accompanied by Mycroft Holmes, follow them across the ocean and discover a structure designed to bring the Old Ones into the human sphere. Yet when it is destroyed people continue to mutate and go mad.