In Whitopolis, a gleamingly white city of the future where illness has been eradicated, shock waves run through the populace when a bedraggled, dirt-stricken boy materialises in the main street. Led by government propaganda, most citizens shun him as a demon, except for Wellesbury Noon – a high school student the same age as the boy.

Upon befriending the boy, Wellesbury feels a connection that he can’t explain – as well as discovering that his new friend comes from a land that is stricken by disease and only has two weeks to live. Why do he and a girl named Ezmerelda Dontible appear to be the only ones who want to help?