Only weeks into their marriage a young couple embark on a six-month period of separation. Tom Cavendish goes to Japan to build lighthouses and his wife Ally a doctor begins her work at the Truro asylum. As the couple navigate their separate professional trials the foundations of their marriage begin to slip. An exquisite novel of the 1880s told in alternating parts: two maps of absence - two distinct but conjoined portraits of loneliness and determination