在这部最终兵器少女 另一曲恋歌动画/短片片中,故事发生在风景如画的北海道小樽市，性格胆小懦弱的千濑（折笠富美子 配音）喜欢上了稳重可靠的修次（石母田史朗 配音），鼓起勇气告白之后，两人走到了一起，并且开始交换日记。
某日，神秘的敌人出现在了札幌市，紧接着到来的是猛烈的攻击，从空袭之中侥幸逃脱的修次看到空中漂浮着少女的身影，她有着钢铁的翅膀和巨大的机械手臂，正在和敌人进行着殊死战斗，令修次怎么也无法相信的是，这名少女正是千濑。原来，千濑被日本军方改造成为了强大的人体兵器，用来和敌人作战，而随着身体的不断改造和能力的不断增强，千濑的精神和肉体都来到了崩溃的边缘。
Lt. Mizuki in JSDF became a prototype ultimate weapon due to serious injury. She and Tetsu was in the same squad before that, and she has been in one-sided love with him. Now, she gets to know transformed Chise as a perfect ultimate weapon. And then, Mizuki understands her suffering because she can hear her inner voice.
战争爱情与幻灭。
