本作改编自真户香的同名小说，是一部以新潟长冈祭大型烟花大会为舞台、描绘缥缈而伤感爱情的故事。高中入学不久后的某日，主人公夏目诚被初次见面的同班同学叶山煌搭话。煌表示自幼便从曾祖母处听闻“终有一天会与夏目诚相遇”，并获赠一幅烟花图画。被这幅承载着“某个约定”的神秘图画所困扰的诚与煌，在有限的时间内被迫做出一个抉择。

Human resources consultant Tsubaki Mako has been dubbed the "devil of human resources" for her iron-fisted ways. She struts her way into a well-established firm and tackles sexual harassment, power harassment, bitter rivalries between factions, and monstrous employees, all of which are issues that can strike any company, with her extreme methods. Mako is like a devil who solves problems with her bold tactics.