The eighth book of the bestselling Rivers of London metropolitan fantasy series returns towards the adventures of Peter Grant, detective and apprentice wizard, as he solves marvelous crimes in the city of London.

Peter Give is facing fatherhood, and an uncertain potential, with equal levels of anxiety and enthusiasm. Rather than sit around, he requires a work with émigré Silicon Valley tech genius Terrence Skinner’s brand new London start up-the Severe Cybernetics Company.

Drawn in to the orbit of Old Street’s famous ‘silicon roundabout’, Peter must understand how to blend in with individuals who are both civilians and geekier than he is. In comparison to his last job, Peter thinks it ought to be a doddle. But magic is not finished with Mama Grant’s most liked son.

Because Terrence Skinner has a secret concealed in the bowels from the SCC. A technology that stretches back again to Ada Lovelace and Charles Babbage, and ahead to the continuing future of artificial cleverness. A top secret that is just as magical since it technological-and just as dangerous.