Doomsday Book is the story of Kivrin Engle, a time traveling historian who travels back to the time of the Black Death. Simultaneously, a wave of influenza sweeps through near-future London and creates a parallel series of deaths and outbreaks. Kivrin and her mentor, Dunworthy, must struggle to make sense of their straits as they try to return to the future but find themselves caught between the two deadly plagues.