The last surviving victim of an experiment that implanted the subjects' heads with electrodes that decipher coded messages is the unnamed narrator. Half the chapters are set in Tokyo, where the narrator negotiates underground worlds populated by INKlings, dodges opponents of both sides of a raging high-tech infowar, and engages in an affair with a beautiful librarian with a gargantuan appetite. In alternating chapters he tries to reunite with his mind and his shadow, from which he has been severed by the grim, dark "replacement" consciousness implanted in him by a dotty neurophysiologist. Both worlds share the unearthly theme of unicorn skulls that moan and glow.