During a fierce battle in Japan's Warring States era, a young swordswoman named Yui is suddenly transported 500 years into the future by the mysterious blade Muramasa. Lost in modern-day Japan, Yui finds refuge at a traditional brewery in Usuki, Oita. While struggling to understand this unfamiliar world, she discovers something she has never seen before: KENDO, the modern martial art descended from the swordsmanship she devoted her life to mastering. The brewery's KENDO club, once proud and successful, is on the verge of collapse. Determined to protect what she believes is worth preserving, Yui helps revive the team alongside Masato Fujii, the brewery's young president and a former national champion who abandoned KENDO after inheriting the family business. As the team prepares for an impossible challenge against their long-time rivals, Yui and Masato grow closer. Yet the possibility that Yui may someday return to her own time threatens the future they are beginning to imagine together.