Mark and Jimmy are "astrological twins" born on the same day, but they have completely opposed personalities. Even so, when they met at university in the 1980s they formed a close friendship, which even survived a crisis point when the reckless Jimmy, having persuaded the sober Mark to sit with him and look after him while he experiments with LSD, accidentally slashed his friend's face with a scalpel. While Mark settled down to teach history at his old school, Jimmy took his biochemical expertise to Big Pharma, where he eventually ended up as a specialist in ethnomedicine, searching the pharmacopeias of primitive tribes in search of exploitable medicines. Periodically, however, he has popped up again to disturb Mark's quiet life, always trying to convince him that his latest method of obtaining drug-assisted access to visions of "hyperreality" will finally lead to success. The latest of those attempts, in 2016, promises to be more ambitious than its predecessors, and also far more complicated, involving both Jimmy's current girl-friend and Mark's wife in an experiment that threatens to change all their lives, as well as revealing discomfiting truths about the true nature of the universe.
