 The Doctor and Donna arrive in what the Doctor believes to be Rome in the first century AD . After an earthquake and witnessing a nearby mountain begin to smoulder , he realises he has in fact materialised in Pompeii one day before the eruption of Mount Vesuvius . When he and Donna return to where the TARDIS landed , he discovers that a local merchant sold it to sculptor Lobus Caecilius . The Doctor and Donna go to Caecilius 's house to retrieve it . Unknown to them , they have been followed by a soothsayer who reports to the Sibylline Sisterhood that the prophesised man in the blue box has arrived , and the Sisters fear the prediction that his arrival brings fire and death . 
