Purkiss’s job is to track down rogue elements within British intelligence. Summoned to Amsterdam to investigate a cryptic message about one such agent, Darius Pope, Purkiss quickly discovers he’s facing an opponent of unusual ingenuity – and capable of extreme violence. Within hours Pope has disappeared, and two CIA agents are dead.

In Virginia, a young musician, Nina Ramirez, finds herself haunted by watchers, men who seem to be stalking her at every turn. Are the watchers genuine, or products of her increasingly troubled mind?

As the body count rises, Purkiss pursues Pope to the eastern United States, desperate to stop him while avoiding a potentially disastrous political confrontation between the CIA and British Intelligence. But Purkiss is faced with two questions: why is Pope systematically murdering CIA agents, and who will be next?

With assistance from an unexpected source, Purkiss discovers he’s in a race against time before Pope’s and Nina’s destinies converge in New York City. Something he’ll be able to prevent only by uncovering the secret of a monstrous, fifteen-year-old Honduran operation known as Caliban…

Darker, harder-edged and more terrifying than Ratcatcher, Delivering Caliban confronts John Purkiss in ways – physically, emotionally, and morally – he’s never yet experienced.