Jeff Somers 
Digital Plague [EPUB ebook] 

THIS IS AN ASSASSINATION. NOT YOURS. BUT AN ASSASSINATION NONE THE LESS.’Avery Cates, criminal 'king’ of New York, has climbed his way to the top of a heap of trouble. On his knees in the snow, with a gun to his head, Avery thinks this must finally be it. Instead, he is injected with nanotech and left confused but alive. Then everyone around him starts dying.With every moment bringing humanity closer to extinction, Cates finds he will be either executioner or saviour of an entire world.