Shogun-sama wa Otoshigoro

A seemingly ordinary high school student named Nobuyuki is transported back to the Edo period following a tragic accident. There he encounters Yoshimune, a skilled swordswoman devoted to justice, Muneharu from a prominent clan, his younger sister Tamaki who also traveled through time, and Rin, a reserved kunoichi living nearby. Armed with a sentient legendary blade called Reitou Retsuzan, Nobuyuki rises to become Edo's greatest swordsman. As various factions pursue a mysterious hidden treasure, a conspiracy unfolds that threatens to shake the very foundations of the Shogunate.