Seiji Takagi, a high school student with a dark desire to kill, finds an unexpected friendship in his skilled rival, Takuma Suganuma. Their bond is tested when Takuma probes into the mysterious death of his sister, leading Seiji to a magical reincarnation in a distant realm. In this new world, Seiji serves as the loyal assistant to Crown Prince Durel in the Kingdom of Instrial, while Takuma rises swiftly in the military ranks under the trust of Second Prince Ashley. As the two friends navigate the political intrigue and power struggle between the royal siblings, they are inexorably drawn towards unraveling the truth surrounding Takuma's sister's demise.