Two and a half years have passed since the Lost July incident, a catastrophe that reduced an entire city to ruins and sent shockwaves across the world. On the desert planet of No Man's Land, Vash the Stampede, a gunslinger who swore never to take a life, faces his final confrontation with his brother, Millions Knives, who seeks the complete destruction of humanity. As their fates collide, the battle that will determine the future of both mankind and the planet begins.

Once a prize-winning violin prodigy, Hajime gave up on music after his father, professional violinist Ryuuji Aono, was involved in a scandal that led the media to harass his family. Now living alone with his mother and entering his final year of middle school, Hajime struggles to find a new career path. However, the sound of his classmate Ritsuko Akine playing the violin inspires Hajime to dream of a musical career once more. With the help of Ritsuko, Hajime prepares to take the entrance exam for the prestigious Umimaku High School. But if he wishes to join Umimaku's orchestra, Hajime must overcome his past trauma and open himself up to new musical horizons.

The entire universe is divided into the inner universe and the outer universe. The two universes are enemies of each other. The outer universe is ruled by demons, and the inner universe is divided into The Realm of gods, the Eternal Realm, and the Mortal Realm. In the universe, there are countless mortal worlds like the Tianfa Continent, and they are collectively referred to as the Jiutian Xin Region. In the field of Jiutian Xin, nine immortal emperors commanded all star fields in nine layers. Above the nine heavens is the realm of purification of immortal gods.

Welcome to the fascinating world of Gensokyo, in which youkai (A term for all sorts of spiritual creatures), animals and some humans live, completely separated from our world by a magical barrier. The only gateway between the two worlds is the Hakurei shrine. Reimu Hakurei is the maiden working at said shrine. Whenever problems of supernatural causes (known as "Incidents") occur, Reimu goes out with her friends to investigate, eliminate the cause and hopefully restore Gensokyo to its equilibrium.