Asamiya-san no Imouto Asamiya Aoi is a mysterious, innocent young girl who is traveling through a futuristic land with the help of her “father’s” sketchbook. One day, Aoi encounters a young woman named Kyoko. She shares her travel plans with Kyoko and shows her the sketchbook. Kyoko can’t believe her eyes! The sketchbook is more like research notes than casual sketches, and it is full of accurate maps and information that she could use to make loads of money. With the original plan of finding a chance to steal the sketchbook, Kyoko feigns concern over Aoi and joins her on her travels. As the two girls encounter and affect the lives of various people on their journey, will Kyoko be able to learn more about this unusual young girl?