Yoichi Karasuma spent his whole childhood in the mountains, where he learned the Soaring Wind, Divine Wind swordsmanship style from his father. His dedication paid off when he reached 17 years old and mastered the technique. His father deemed him ready to continue his training at a new dojo in the bustling city. However, Yoichi's lack of familiarity with modern society posed a challenge. He struggled to communicate and acted like a traditional samurai, wearing traditional clothing and using archaic language. When he moved in with the Ikaruga sisters at the dojo, Yoichi's social ineptitude led to many comedic misunderstandings. As Yoichi tried to adjust to his new life and understand contemporary ways, Asu no Yoichi! captured his misadventures with his new family.