The narrative centers on Kazuya Shibuya, a young man who unexpectedly receives an anonymous email one day reading: "Won't you join the Savanna Game?" This message serves as an invitation to a state-sanctioned killing game—a lethal role-playing contest intended to motivate the inhibited youth of modern Japan. Shibuya, along with his two friends Kotegawa and Kudou, finds themselves engaged in bizarre battles that traverse the space-time continuum, featuring everything from dragons to the Shinsengumi force of the shogunate era.