The Ellsworth community is growing on Earth. But have they really solved the problem that wiped out Earth's population? Twenty years have passed since they returned from space. Nothing has been heard from Ararat. Will the colony finally respond when they know the problems found on Earth? And what happened to Nels and his little group? The distances involved between the planets make communications difficult. Messages are out-of-date by the time they arrive ten years later. Where does the future of mankind lie?