Two sisters, one from a megacity and one from the wilderness, work together to protect the wilderness and the reintroduction of wolves from a group more interested in private property than public good. In a future Earth that's run by brilliant green cities separated by open land held in common for the good of wild things, two sisters must work together across and between the vastly different environments to root out dangers to both. They must protect the cities and the wild from the Returners, who prefer the toxic past to the difficult present. The older sister, Lou, her protector Shuska, and biologist friend Matchiko have reputations as successful rugged environmentalists. They must stay safe, listen, work, and sleuth out hidden nests of Returners. Oh, and save a few wolves along the way. In the meantime, Lou's younger sister, Coryn, is learning that working for the most powerful woman behind the scenes in a megacity is far harder than it looks. When the Returners threaten the city, the sisters must find a way to preserve both their ways of life. Keepers asks, Do humans have enough creativity, responsibility, and generosity to survive?