On the planet Talos VII, twenty-three years before the events of To Sleep in a Sea of Stars, an anomaly is detected: a vast circular pit, with dimensions so perfect that it could only have been the result of conscious design. So a small team is assembled to learn more - perhaps even who built the hole and why. Their mission will take them on a hazardous trek to the very edge of existence.

For one explorer, this is the opportunity of a lifetime. For another, a risk not worth taking. And for xenobiologist Alex Crichton, it's a desperate attempt to find meaning in an uncaring universe. But every step they take towards that mysterious abyss is more punishing than the last. Ultimately, no one is prepared for what they will encounter.