It is part of the Rocheworld series, about an expedition to explore planets found in orbit around Barnard's Star.

In this novel, after settling down on the habitable moon Zuni (now known as Eden), the crew struggle to survive various disasters and to communicate with a mysterious Civilization under the ocean.

The first interstellar expedition successfully reached Barnard's Star and its double-planet Rocheworld and made contact with the flouwen, intelligent aquatic beings with a talent for higher mathematics and a love of surfing.

When a landing craft carrying ten humans and three flouwen crashlanded on a habitable moon—Eden—the team was marooned on Eden with no hope of rescue until decades later when a second expedition was scheduled from Earth.

A new generation grows up hearing of Earth and its technology as a dim legend, and thinking of Eden as their natural home.