A science fiction novel set in the year 2137, where humanity has colonized the moon and Mars. The story follows a team of scientists and engineers who are sent to explore the outer reaches of the solar system, including the gas giant Neptune. They discover an alien spacecraft on the bottom of the ocean, which they believe could hold the key to understanding the origins of life in the universe. However, their mission is threatened when they realize that the alien race that built the spacecraft may still be alive and hostile towards humans.
By Isaac Asimov · First published 1977 · Genre: Science Fiction, Adventure, Speculative Fiction · 8 chapters