In the near future, a government ministry is gathering "expats" from across history to establish whether time travel is feasible - for the body, but also for the fabric of space-time. A civil servant is tasked with working as a "bridge" - living with, assisting, and monitoring the expat known as Commander Graham Gore. As far as history is concerned, Gore died in 1845, so he's a little disoriented to be living with an unmarried woman. By the time the true shape of the ministry's project comes to light, the bridge has fallen in love, with consequences she never could have imagined. The bridge must finally reckon with how what she does next can change the future.