Eilis of the Underground takes place in a world divided. The surface dwellers, Balisks, live comfortably in the harsh cold, while the ones living underneath, Delphs, survive in a warm pocket deep in the ground. The two coexist, but keep to themselves. Enter: Eilis O’Rinn, a Delphic private investigator who must deal with both Balisks and Delphs. Walking the line between the surface and the underground, because she no longer belongs to either.