Book excerpt: From the author of Thirteen Hours - A Sunday Times '100 best crime novels and thrillers since 1945' pick An antiques dealer is burned with a blowtorch and executed with a single shot to the back of the head. The only clues at the scene are a scrap of paper and an unusual choice of gun. Ex-cop Zatopek 'Zed' van Heerden has just seven days to solve the case - an almost impossible task made even harder when he discovers that, until a few years ago, there was no proof that the victim even existed . . .