2014: A great poem is read aloud and never heard again. For generations, people speculate about its message, but no copy has yet been found.

2119: The lowlands of the UK have been submerged by rising seas. Those who survive are haunted by the richness of the world that has been lost.

Tom Metcalfe, an academic at the University of the South Downs, part of Britain's remaining island archipelagos, pores over the archives of that distant era, captivated by the freedoms and possibilities of human life at its zenith. When he stumbles across a clue that may lead to the lost poem, a story is revealed of entangled loves and a crime that destroy his assumptions about people he thought he knew intimately well.