Former correspondents E. and Henerey, accustomed to loving each other from afar, did not anticipate continuing their courtship in an enigmatic underwater city. When their journey through the Structure in E.'s garden strands them in a peculiar society preoccupied with the pleasures and perils of knowledge, E. and Henerey come to accept-and, more surprisingly still, embrace-the fact that they may never return home.
 
A year and a half later, Sophy and Vyerin finally discover one of the elusive Entries that will help them seek their siblings. As the group's efforts bring them closer to E. and Henerey, an ancient, cosmic threat also draws near...