The story of three high school students who must overcome the boundaries of time and dimensions in a death spiral to save their world from higher beings who threaten their world.

In the mid-2020s, Kobayashi Kuro, Sakiko Miyu and Sakurano Aihara are about to enter their final year of high school. Kuro has just returned to his old home, which he left as a child. Miyu and Aihara can't stand each other and Kuro is always the one caught in the middle. Time and again, he more or less involuntarily ends up with one of the girls who has romantic feelings for him. Kuro soon realizes that his life consists of more than just teenage love dramas when his teenage life suddenly turns into a cruel playing field of higher beings from higher planes of existence from which there is no escape. Kuro must confront the power of time manipulation and travel through an alien dimension to save Miyu, Aihara and himself from an ever-repeating spiral of death. On his journey, Kuro must learn more about his old home, an old legend about his family and fathom his own heart, that of the two girls and that of his enemies in order to win the game.