Light is set in the early 1830s on a small island off the Isle of Man. Two surveyors arrive to start working on a modern lighthouse to replace the ancient light which, for generations, has been tended by the only family on the island. The surveyors, who work for Robert Stevenson, the famous Scottish lighthouse engineer, are billeted with the family. Inevitably, misunderstandings and tensions arise. The women who keep the light see this new intrusion as a threat to their way of life. For their children it is both an adventure and yet another inscrutable display of adult behaviour. And for the surveyors it is simply another job, which suddenly becomes unexpectedly complicated.

When the weather changes and the surveyors are storm bound, relations on the island reflect the growing storm offshore. This novel features life on the edge, physically and culturally, as the traditional rhythms and values of a remote island society encounter the self-confident forces of the Edinburgh Enlightenment and advancing technology.