It seems as if not all copies of 'The Book' of destiny have been destroyed, and one of its prophecies - that of the appearance of The Four Horsemen of the Apocolypse - has become true. The Horsemen have arrived on their different coloured horses: one Black, one White, one Pale and one Pink, and are searching for Rex Boggs - Wizard of Limbo - who prevented their arrival on Hove seafront by rewriting the future. Meanwhile, on a small island in the Great Barrier Reef, Nilbert Plymstock - maverick genetecist - is searching for a way to save the dying reef by tampering with the corals' DNA. What his research leads to is the development of a biological computer whose processsing power is off the scale. Back in Limbo, Queen Iris Boggs is bored with her regal life and goes back to Lancing to work in her old newsagent's shop. Unfortunately, she is apprehended by the Four Horsemen and held hostage. Things get even more complicated when Nilbert's computer comes up with a formula for predicting the future, and the Horsemen become hell-bent on opening Pandora's Box - hidden deep in the middle of Dartmoor.