Transported to 1789 Japan during the peaceful Edo period, the protagonist starts with only a low-ranking samurai identity, a sword, and a system that enhances his stats and swordsmanship by defeating or killing enemies. He's known by titles such as "Manslayer Itsuse" and "Executioner Ichi-no-Sai." When facing strong opponents, he'll switch to his real specialty—dual wielding. If that fails, he'll use his revolver. This is the story of a great swordsman.