At sixteen, Sanae and her friends are starting a new year at middle school. But at their first kendo training, they meet Kaori, who is a very serious loner. After their intense practice bouts, Sanae realizes that Kaori is the regional champion who she accidentally beat the previous year. Kaori has transferred to their school with the sole purpose of meeting with Sanae and beating her, and is devastated to discover that Sanae is not serious about the sport. Kaori takes up a personal challenge to train Sanae until she is a worthy opponent.