In the near future, a disaffected civil servant is offered a job in a new government ministry gathering 'expats' from across history to test the limits of time-travel. Her role is to work as a 'bridge': living with, assisting and monitoring the expat known as '1847' - Commander Graham Gore. As far as history is concerned, Commander Gore died on Sir John Franklin's doomed expedition to the Arctic, so he's a little disoriented to find himself alive and surrounded by outlandish concepts such as 'washing machine', 'Spotify' and 'the collapse of the British Empire'. With an appetite for discovery and a seven-a-day cigarette habit, he soon adjusts; and during a long, sultry summer he and his bridge move from awkwardness to genuine friendship, to something more. But as the true shape of the project that brought them together begins to emerge, they are forced to confront their past choices and imagined futures.