This first in a "fresh new sci-fi" (Jason M. Hough, New York Times bestselling author) series follows a powerful woman who can destroy planets with a single word but is suddenly faced with an adversary that threatens the entire known universe.

Far in the future, human beings have seeded themselves amongst the stars. Since decoding the language of the universe 8,000 years ago, they have reached the very edges of their known galaxy and built a near-utopia across thousands of worlds, united and ruled by a powerful organization known as the Ascendance. The peaceful stability of their society relies solely on their use of this Deep Language of the cosmos.

But this knowledge is a valuable secret, and a holy order of monastics known as the First House are tasked with monitoring its use and "correcting" humanity's further development. Elyth is one such mendicant, trained as a planetary assassin, capable of infiltrating and ultimately destroying worlds that have been corrupted, using nothing more than her words.

To this end, Elyth is sent to the world Qel in response to the appearance of a forbidden strain of the Deep Language that was supposed to have died out with its founder over seven hundred years prior. What she finds on the backwater planetoid will put her abilities to the test and challenge what she knows of the Deep Language, the First House, and the very nature of the universe.