Okawa Yuka is living out the daily motions of life but doesn't understand her reason to keep living. After a confrontation with a co-worker, she decides to end it all but fails when she stops herself from squishing a cicada. That cicada returns the favor by transforming into a man, named semi, for seven days because he thinks it will make her happy. The downside is, he has no idea how to live as a human.

东京郊外的公寓“现世庄”，虽然建筑有点老旧，但这栋有品位的英国风格公寓里生活着很多个性十足的人。蝉就在公寓的庭院中诞生，多少年来一直蛰伏在地下，等待羽化的一天，当这一时刻终于来临，他满怀期待从土里露出头，向往着蓝天白云，不料却遇到了由香，差点被她压在身下，从此他波澜万丈的人生拉开序幕。由香很机灵，蝉没有被压扁，却注意到她落寞的神情，蝉希望变成人的样子，让她露出笑容，于是他真的变成一名男子出现在由香面前，为了报恩与她开始七天的限定生活。