Murder-mystery/brain-puzzler, set in 2030, in which narrator Peter Ambrose--who makes his living installing ``virts'' (specialized interactive computer chips) in the heads of his clients--wakes one morning to find his computer displaying the hologram of a recent murder victim. Why? Well, the dead man is an old colleague from a mysterious past that Peter has blocked off from his memory--a past involving experiments in mind control during the horrid Wars of Devolution. Other members of the Nimbus group soon come to Peter's attention: Tony Wadkins blows up the corpse that Peter has gone to investigate--forcing Peter to approach his ex-wife, Corinne, to help him recover his scattered memories. Murders of more Nimbus members follow, leading Peter to suspect the involvement of Nimbus's old leader, Linden Straussmann. But Straussmann has been dead for years; the other Nimbus people have gone their separate ways and disclaim all knowledge of the killings--indeed, Peter himself becomes the prime suspect and is himself nearly killed by a desperate Wadkins. Then he recalls installing a particular virt in the brain of Gideon Farley, Corinne's husband--a virt constructed by another Nimbus member for purposes unknown. Hard-working, with fine ideas well worked out, but wildly overdetailed and involuted; the contrast between Jablokov's excellent characters (especially the women) and his mushy, juvenile-sounding protagonist is particularly unfortunate. Better than the mediocre A Deeper Sea (1992), not as good as the splendid Carve the Sky (1991).