Sharp little murder mystery with serviceable characters elevated by its setting. Would recommend for sci-fi fans like myself (especially the gay ones) who don't typically stray into mysteries/thrillers because it takes place on a large-scale Earth-orbit station where humans fled after environmental collapse and there's an entire university dedicated to the study of Earth ecosystems so that one day they can play God well enough to restart life on Earth in perfect balance with humanity. Not everyone agrees on that goal, or when we're ready to try Earth 2.0. The plot interacts with all these viewpoints and it's fun food for thought.