In post-World War 2 Japan, a farm girl arrives in Tokyo and starts a career in animation.

The story is set during the high economic development time of the Showa period. Natsu lost her parents during the war so she moves to the Tokachi region in Hokkaido with her foster father who is a dairy farmer. While growing up, Natsu meets a boy at primary school who draws a very beautiful picture of a horse so she becomes interested in animated movies. Upon graduating from senior high school, Natsu moves to Tokyo and joins the budding animation industry in order to fulfill her dream of becoming an animator.