her engagement ring. 1.5 carat, almost flawless. But the Promisor had other ideas for their future... Their murder - and that of the diamond cutter they were visiting - is only the first of a series of macabre attacks. The killer is hunting down any witnesses who might lead to his capture. He has promised one thing: to destroy. But Rhyme and Sachs will do whatever it takes to break his vow.