Dunworthy keeps changing their assignments at the last minute, for reasons not explained until All Clear. It is the year 2060, and the historians (time-traveling research staff) at Oxford University are a hair's breadth away from revolting. The 21st-century authorities controlling time-travel also have rules and can deem some historical periods too dangerous for time-travel, even though those times might be theoretically accessible. Once a time-traveler has visited a certain date, he or she can never go to that same time again. In addition to slippage, which the technicians operating the net cannot control or predict, there are other reasons why a historian might not be able to travel to a certain time. An example is when the character Polly wishes to arrive on September 10, 1940, in London, but instead arrives on September 14.

The time-traveler arrives at the nearest place and time suitable for preventing a time paradox although sometimes this is only a few minutes later than planned, it can be as much as several years. In other cases, 'slippage'-a shift from the exact, desired target in time and/or space-occurs. In some cases, the machine used for time-travel will refuse to function, rendering the trip impossible. Historians in Willis' world believe that the laws of physics resist possible alterations to the past by preventing time-travel to certain places or times. They can return from the same location when someone in the future re-opens the Net for them at an agreed-upon 'rendezvous' time. The time-travel device, a portal called 'the Net', remains in the time-traveler's present, while sending the time-traveler to a particular location (called 'the drop') and time. In their world, time-travel has been known since the early 21st century. The research is mainly conducted at the University of Oxford in England in the mid-21st century. Willis imagines a near future (first introduced in her 1982 story ' Fire Watch' and featured in two of her previous novels: Doomsday Book and To Say Nothing of the Dog) in which historians conduct field work by traveling into the past as observers. These two volumes are the most recent of four books and a short story that Willis has written involving time travel from Oxford during the mid-21st century, all of which won multiple awards. The diptych won the 2010 Nebula Award for Best Novel, the 2011 Locus Award for Best Science Fiction Novel, and the 2011 Hugo Award for Best Novel. The second part, the conclusion All Clear, was released as a separate book on October 19, 2010. Locus Award for Best Science Fiction Novelīlackout and All Clear are the two volumes that constitute a 2010 science fiction novel by American author Connie Willis.

Blackout by Connie Willis