In the year 2006, Spring. 6th-grade elementary schooler Shimada Chika was fed up with her mother who kept preparing food for her brother, Takashi, who was run over by a truck last year. Chika was able to stay patient with everything else, but she was annoyed from the bottom of her heart with the new hobby that her mother started. Fumie operated the PC awkwardly, and wrote a light novel using the plot that Takashi left behind. It was a fantasy novel about Takashi being reincarnated in a different world, and used the knowledge of the present world to make weapons and stood against the demon lord. Chika, who wanted her to stop writing, consulted the former driver who hit her brother with a truck, Katayama., but Katayama was fascinated by the novel that Fumie wrote, and proposed a certain plan to Chika—.