A pilot from Earth is called upon to ferry a dignitary to the utopian colony on the surface of the Moon, where she finds herself caught up in a mystery much deeper than the murder of a sister she never knew.
While Indira attempts to convince Maite Voss to step aside from her position on the lunar council, Paul and Arlo investigate a second murder – and Bella struggles to find a way out.
While Bella and Paul investigate the underground responsible for the Singer she was smuggling, Indira's efforts to finally complete her lifelong mission prompts her to recall her childhood.
Indira, Bella, and the others narrowly escape an attack by an apparent Mooner separatist group, who may be working against the Bridge on the eve of its opening. As Bella and Indira try to get through to Maite Voss, Paul receives word that his birth mother is near death.
Bella and Paul strike out into the wild lands of Primo in search of Maite. As Arlo works to solve the riddle of the compass rose, Tom puts in motion a plan that could unravel the fabric of Mooner society.
When the Envoy declares martial law and attempts to exile Bella, she and her new friends search for a way to save the dream of Moonhaven -- as Tom and the rebels attempt to seize control of the colony.