The novel is set in two eras. In 2020, the U.S.S. Lewis & Clark, commanded by Colonel Shaun Christopher, is on a mission to Saturn. But Colonel Christopher and his crew are surprised to discover that the rings of Saturn are not behaving as they had expected. Centuries later, Captain Kirk and the U.S.S. Enterprise respond to a distress call from a colony on the moon of the ringed gas giant Klondike VI. The planet’s rings are beginning to disintegrate, and the resulting bombardment of ring-fragments threatens to destroy the colony. What is the connection between these two events, taking place in different time-periods and different parts of the galaxy? And what is the secret of the mysterious probe that appears to be involved in both eras, and both situations?