Spares — Michael Marshall Smith

They were raised for one chilling purpose....

A loner, an ex-cop, Jack Randall is the dangerous veteran of a savage war. All he's held dear has long been destroyed. For the last five years, he's been hiding out on a Spares Farm, guarding those who've been prisoners from birth. Now he's on the run with seven of the Farm's inmates (well, six and a half), and the people who own them will do anything to get them back. What's worse, Jack is on a head-on collision course with a cold-blooded killer with one purpose: to cancel Jack once and for all. Jack has a tough decision to make: keep running or even the score. Either way spells trouble...the kind of trouble most people run screaming from.

Who are the Spares? And what is their purpose? That is the most shocking revelation of all.