The protagonist Ka and ride the central live in Okinawa , a very ordinary high school students . Anniversary of the death of the 5th generation of elders , chanced to meet a cat ear girl and his father drinking beer . The girl said named Alice is Kati Ya to the Earth's purpose is to play the way to do research . Since then , she have been the secret organization , government, and fanatics who apprehend murder . Riding central in order to protect her , and set foot in uncharted territory .