After a devastating fire ravages their village, Shino, Sousuke, and Hamaji face a fateful encounter with a mysterious man wielding a sword amidst the flames. Their lives take a drastic turn as they are given a choice that will determine their survival. Fast forward five years, the trio finds themselves living under the protection of the Imperial Church, until their peace is shattered by the Church's pursuit of the demonic sword Murasame. When Hamaji is abducted to lure Shino, now the sword's bearer, and Sousuke, who can transform into a canine, the brothers must unite to rescue her from the clutches of the Church in the Imperial Capital, embarking on a challenging journey ahead.