When artist Simon Dykes wakes after a late night of routine debauchery he discovers that his world has changed beyond recognition. His girlfriend Sarah has turned into a chimpanzee. & to Simons appalled surprise so has the rest of humanity. Simon under the bizarre delusion that he is human is confined to an emergency psychiatric ward. There he becomes of considerable interest to eminent psychologist & chimp Dr Zack Busner. For with this fascinating case Busner thinks may finally make his reputation as a truly great ape.