There is only one police officer in the small town of West Woodburn, England. His name is Forty-Two, and he is a Dog. Genetically engineered and bred to conform to the ideal standard, he can do anything a human can. His kind are so dedicated to their task that society no longer sees any reason to pay for human police.

Forty-Two's quiet, rural life is shattered when a murderer begins stalking everyone the Dog has ever called friend.

The greatest scientific advancements come from war, and the Dog program is no exception. Originally developed as living weapons for World War II, it wasn't long after that they were repurposed to their current role. It's only been fifty years, and not all men have forgotten that Dogs, like their masters, fought on both sides.

Forty-Two must track down the killer and suppress the case before an inquiry can be launched. Any investigation into Forty-Two's own past would reveal that he too has secrets to hide. While he is far too young to have any memories of war, Forty-Two's unmasking would destroy all confidence in the Dogs that now carry the justice system.

Back in West Woodburn, the young Jonathan Hyatt is laid to rest, but peace does not come quickly. The Master Constable has arrived, and Forty-Two must fight to put out the flames.