The tale follows the journey of Sayaka and Mushin, lifelong friends and skilled kendo practitioners. Mushin admires Sayaka's strength, yet harbors a desire to protect her. Unbeknownst to him, Sayaka is the one who safeguards him whenever he's in peril. Adding to their challenges are numerous nemeses, including malicious entities attempting to obliterate their dojo, and amorous rivals vying for the duo's bond. Nonetheless, with Mujin's forthright sincerity and unwavering goodwill as a potent weapon, the companions press onward, facing daunting hurdles that demand cooperation - starting with the fact that they're step-siblings.
