The second generation of Honda's popular Fit (Jazz). It was a world car sold all over the world and manufactured in eight countries, procuring manufacturing parts from various countries. Honda has been promoting the relocation of its manufacturing bases and headquarters outside of Japan for some time, and the second-generation Fit is the result of that effort. The Fit continues to adopt the center tank layout (the fuel tank is located under the floor in the center of the car body), which minimizes the characteristic of automobiles that fuel tanks squeeze the interior space, and achieves an interior space that is undesirable for the size of the body. The Fit, on the other hand, is often thought of as just a utility vehicle with a spacious interior, but its low center of gravity and compact, lightweight chassis make it a very capable cornering vehicle. The Fit are recommended by Japanese racing drivers and many other drivers as a car to improve their driving skills, and are known for their straightforward handling and excellent characteristics.

Yuna Yuki, age 13. She joins the Yuusha Club. Yuna Yuki wakes up in the morning, gets ready, goes to school, takes classes, does club activities, and plays with friends. She is a second-year junior high school student going about her normal daily life. The only special thing about her is that she belongs to the "Yusha Club. What are its activities? What is the mysterious existence, Vertex? This is a story of girls in the 300th year of the Divine Century.

Yuna's classmate and best friend. She is very understanding of Yuna. They live next door to each other, and often acts together. She is elegant and calm, but she has a thorough knowledge of computers, baking, and other things, and sometimes shows a geeky side to friends.