On ritual occasions Plato, the orator, summons the citizens of London to impart the ancient history of their city, dwelling particularly on the unhappy era of Mouldwarp (AD 1500-2300). He lectures on The Origin of Species by the nineteenth-century novelist Charles Dickens and on Sigmund Freud; whilst providing a glossary of twentieth century terms, and explaining such early myths of creation as 'super-string theory' and 'relativity'. But then he has a dream, or vision, or he goes on a real journey - opinions are divided - and enters a vast underground cavern, where citizens of Mouldwarp London still live. On his return, Plato shares his stories of this lost world, but his words spread consternation among his fellow citizens and they quickly put him on trial for corrupting the youth with his lies and fables.