On the edge of No Man's Land, Clocktower Fortress stands solitary. Within it resides the 1121st Platoon of the Helvetian Army, where a 15-year-old volunteer named Kanata Sorami eagerly joined to learn the art of playing the bugle. Ever since she was young, a brave soldier had rescued her, and the clear, golden tones of the soldier's trumpet had been an inspiration to Kanata, leading her to pursue a life in music. As Kanata devotes herself to mastering the bugle and becoming a true soldier, her unwavering positivity rubs off on her comrades, encouraging them to discover beauty and joy in a world plagued by war.