Circulum

For four hundred years the Lethic Signal has arrived from beyond the sky, unchanging, undecoded, and copied by hand into the sealed archives of Atheln's research compounds. Then Aldren Corris finds a flaw in a fresh transcription — the first change in the Signal's history — and learns that a reclusive theorist predicted it, then buried the proof. Soldiers are massing outside the walls. The Signal is no longer only speaking. It is answering.