Kuro Fukase, embittered and alone, finds solace in the Ayakura sisters until tragedy strikes. With his companions gone, he harbors a deep-seated animosity towards society. Everything changes on a fateful Christmas Eve when he encounters the enigmatic Sera Himeura, the intriguing witch Yume Furusuna, and a mysterious black entity. Unveiling his role as one of the 20 'Instant Bullets' with the capacity to bring about the world's demise, Fukase is thrust into a conflict of diverging intentions among these living weapons. As some seek salvation while others, like Fukase, crave destruction, the narrative delves into a riveting exploration of past scars, moral ambiguity, and complex relationships. Amidst this turmoil, the question arises: what fate awaits a world torn apart by the clash of these powerful beings?