Set in a dystopian Earth where the soviets have returned to power in Russia, Alastair Reynolds gives us a story about human courage, and hope from a structure who's sole purpose is to deliver a message through time. It is a short novella and has the usual Reynolds feel to it: big, mysterious, and hard physics. A very enjoyable read, but the ending leaves many unanswered questions. I wouldn't mind if he did more shorter stories like this and released them as e-books to fill the gaps between major novels.