Lake of Souls by Ann Leckie

Hugo, Nebula, and Arthur C. Clarke award-winner Ann Leckie is a modern master of the SFF genre, forever changing its landscape with her groundbreaking ideas and powerful voice. Now, available for the first time comes the complete collection of Leckie's short fiction, including a brand new novelette, "Lake of Souls."
Journey across the stars of the Imperial Radch universe.
Listen to the words of the Old Gods that ruled the Raven Tower.
Learn the secrets of the mysterious Lake of Souls.
And so much more, in this masterfully wide-ranging and immersive short fiction collection from award-winning author Ann Leckie.