In the novel's somewhat dystopian world, human personalities can be stored digitally and downloaded into new bodies, called sleeves. Most people have cortical stacks in their spinal columns that store their memories. If their body dies, their stack can be stored indefinitely. Catholics have arranged that they will not be resleeved as they believe that the soul goes to Heaven when they die, and so would not pass on to the new sleeve. This makes Catholics targets for murder, since killers know their victim will not be resleeved to testify. A UN resolution to alter this legal position forms one strand of the novel's plot, to allow the authorities to sleeve a deceased Catholic woman temporarily to testify in a murder trial.

Some 30 years after Altered Carbon, Takeshi Kovacs is now serving in Carrera's Wedge, a mercenary organisation which joins a corporate war on a distant colony, Sanction IV, and fights the rebellion against the corporate-sponsored government. While having his latest body repaired after a disastrous campaign, Kovacs is approached by pilot Jan Schneider, who is looking for protection for an expedition to exploit a Martian artefact discovered just before the war broke out. "Martian" artefacts have been known for many years at this point, one of them being featured in Altered Carbon. Later it is realised that the "Martians" were not from Mars, but were a technologically advanced species that left artefacts on many planets, including Mars and Kovacs' home world.

In a world where the real and virtual are one and the same and the dead can come back to life, the damsel in distress may be none other than the infamous Quellcrist Falconer, the vaporized symbol of a freedom now gone from Harlan's World. Kovacs can deal with the madness of AI. He can do his part in a battle against biomachines gone wild, search for a three-centuries-old missing weapons system, and live with a blood feud with the yakuza, and even with the betrayal of people he once trusted. But when his relationship with the Falconer brings him an enemy specially designed to destroy him, he knows it's time to be afraid.