You died. At least, Kovacs thought so. He saw with his own eyes how you, his best friend, were shot in chest during Battle of Stromhold, where all the other Envoys, except him, died. After 250 years of cryosleep and completion of investigation of Bancroft case, he decides to return to planet Harlan, where he will learn something that will turn his whole world upside down - your cortical stack remains intact. If he finds it, he can upload your consciousness into a new sleeve. And he will find.