In the novel's cyberpunk and bleak world, human personalities can be stored digitally and downloaded into new bodies, called sleeves. Most people have stacks in their spinal columns that store their memories. If their body dies, their stack can be stored indefinitely.

The protagonist Takeshi Kovacs was an Envoy, a member of a military unit formed to cope with the challenge of interstellar warfare. Faster-than-light travel is only possible by transmitting a digitally stored consciousness across space into a new sleeve.

Now he is a mercenary digitally transfered to earth to solve the murder of a powerful businessman.