Plot: The world is covered with fine dust, and Cs, who were injected with expensive antibodies at birth, enjoy a life expectancy of 100 years, while Ns, who were not injected, live a completely different life, with a life expectancy of just 30. Having lived her entire life as a C, 26-year-old college student Io finds out that she was not given the antibody injection at birth thanks to a mistake at the hospital