Mizunashi You remembers his youth in Cambodia, when he stays with his grandfather, a surgeon in volunteer medic team sent to help the victims of war. But he had blanks in those memories.
During his high school year, he often got bullied because his family owns a hospital, meaning he's rich. Then, one day, You meets with a man introducing himself as R (From Ray Bradbury's novel, "R is for Rocket"). R asked You for help in exchange for information. But both of them don't realize that the information You wanted leads to a larger plot.