“A Half-Built Garden” is a very different type of novel by Ruthanna Emrys. It could be classified as solar-punk as well as first contact. It’s set in 2083, and there has been a bottom-up ecological and social revolution. The Watersheds are the predominant organizations, and they seek to save the world from climate change and the legacy of pollution. National governments have become secondary, and corporations have been exiled to their enclaves where they maintain their own strange complex cultures. The world is improving slowly rather than getting worse, so humanity has reason for hope. Then the two types of aliens arrive. They set their damaged starship down in Chesapeake Watershed, and begin broadcasting based on intercepted human signals. They are here to rescue us, as in their experience, sapient species must expand into space to survive. Those that do not leave their home worlds die along with those worlds when their technological evolution destroys the biosphere of their planets. They have followed electromagnetic signals to find two extinct species so far. Humanity is the first species they have found out of their home star system that is still living. This is the crux of the novel, the aliens believe they have to save humanity from the ecological collapse of the Earth. Most of humanity has become dedicated to preventing that collapse, and believes it is making progress. Can these two ideologies and three species come to symbiosis?