Two thousand years in the future, the Moon has become a run down experiment in terra-forming and colonization with a dusty patina and a bright red sky. To sixteen-year-old Hieronymus Rexaphin, however, it is the only place he has ever known until he meets a girl from Earth called Windows Falling on Sparrows. Windows Falling on Sparrows is inexplicatly drawn to him because of his special, some say dangerous, condition. Hieronymus is a One Hundred Percent Lunar Boy who can see the fourth primary color, giving him the ability to see the future path of time and matter. To look into his eyes will cause madness or even death, authorities say, so he is forced to wear goggles. The color of his eyes is against Lunar law, and some say against nature. After breaking the Moon's most serious law and exposing his eyes to a curious young Earth girl, Hieronymus embarks on a misadventure to protect his friends and save his family, and to escape exile and imprisionment on the far side of the moon.