Shogo Mikadono is the son of an industrial magnate named Kumagoro Mikadono who passed away. As a final wish, Kumagoro imposed a condition Shogo must meet before he can inherit the family legacy—find a female mate at school. Shogo transfers into a school to fulfill that condition. However, he learns that he has a younger sister from whom he was separated at birth. He does not know what his long-lost sister looks like, but she happens to be one of the students at his new school.

故事发生在私立高藤学园的校园中，这一年，童年好友大岛祐树（中村悠一 配音）和住吉千里（中村绘里子 配音）共同升上了二年级。作为在校学生，课后的社团活动是校园生活必不可少的一部分，祐树和千里伙同同学木场冬美（水桥香织 配音）一同组织了“食品研究部”。说是研究部，其实不过就 是大家在一起分享美味的零食，但这简单的活动带给了女孩子们无比美好的课后时光。 不幸的是，研究部最大的敌人东云皐月（浅川悠 配音）发出了“解散没有实际成绩的社团”的宣言，而他本人很可能即将当选学生自治会的会长。为了保护心爱的社团，女孩子们决定以竞争对手的身份加入竞选，一场轰轰烈烈的社团保护战开始了。

自古以来，生灵万物自出生时就带来了两股能量——幸福的能量和不幸的能量。然而日本的佛女津市这两股能量的平衡却遭到了破坏。神明界掌管幸运与不幸平衡的穷神会派出穷神红叶（内山夕实 饰）下凡到人间调查破坏运气秩序的元凶樱市子（花泽香菜 饰）。16岁的高中生樱市子是一名集美丽、智慧、财力、运动细胞于一身的天生幸运儿，她从出生就不知道什么是努力和失败。红叶用观察幸福与不幸能量值的眼镜看出原来樱市子不仅幸福的能量值大大高于常人，还在不断汲取着别人的幸福能量。红叶断言如果樱市子继续不断吸收别人的幸福能量的话，将会招致身边人变得不幸。于是红叶宣布要废掉樱市子吸收幸福能量的能力并且把她多得离谱的幸福能量还回它们应有的地方……

In the year 2022, a massive online role-playing game called Sword Art Online (SAO) is launched. With the aid of "NerveGear" technology, players can control their avatars within the game using nothing but their own thoughts. Kazuto Kirigaya is among the lucky few who get their hands on the first shipment. He logs in to find himself, with ten-thousand others, in the scenic and elaborate world of Aincrad. However, in a cruel turn of events, the players soon realize they cannot log out; the game's creator has trapped them in his new world until they complete all one hundred levels of the game. In order to escape Aincrad, Kirito will now have to interact and cooperate with his fellow players. Some are allies, while others are foes. Sword Art Online is not all fun and games: if they die in Aincrad, they die in real life. Kirito must adapt to his new reality, fight for his survival, and hopefully break free from his virtual hell.

曾经热爱唱歌的坂井和奏（高桓彩阳 配音）在母亲去世后就此紧闭了双唇，愧疚和悔恨一直折磨着她脆弱的灵魂，这也导致本来在年音乐特长班的她转到了普通班。一次偶然中，和奏认识了同班同学宫本来夏（瀬户麻沙美 配音），来夏对音乐的热爱感染了和奏，也唤起了她对于音乐久违的热情。冲田妙羽（早见沙织 配音）的出现彻底奠定了和奏重拾音乐的决心，合唱部应运而生。 随着维也纳转学生前田敦博（花江夏树 配音）的出现，合唱部的人气达到了顶峰，有了音乐的每一天，和奏都和伙伴们快乐的渡过着，母亲坂井真昼（大原沙耶香 配音）给和奏带来的困扰也逐渐的转化为了生活的动力。