London, 1861. Sir Richard Francis Burton - explorer, linguist, scholar, and swordsman; his reputation tarnished; his career in tatters; his former partner missing and probably dead. Algernon Charles Swinburne - unsuccessful poet and follower of de Sade, for whom pain is pleasure, and brandy is ruin! Their investigations lead them to one of the defining events of the age, and the terrifying possibility that the world they inhabit shouldn't exist at all!
