Against Gravity

Against Gravity is a stunning sci-fi thriller from Gary Gibson, author of the Shoal Sequence. In the late twenty-first century, you will find a very different world. Little is as it used to be, and many are not what they seem. Kendrick Gallmon, survivor of an infamous research facility called the Maze, is trying to pick up the pieces of his life, even though he knows the Labrat augments are slowly killing him.
Then one day his heart stops beating, forever, and a ghost urges him to return to the source of all his nightmares, a long-abandoned military complex filled with entirely real voices of the dead.