Semi the cicada was born in the gardens connected to Utsusemiso, an apartment building on the outskirts of Tokyo. He grew underground for several years and when he finally surfaced, he was nearly crushed under a woman who had fallen. She is Okawa Yuka, a resident of Utsusemiso. Yuka works for a food company and has never had a day when good things happen to her. Although she was saved from being crushed by her quick wits, Semi feels the loneliness of her. Out of a burning desire to make her smile, he transforms into a human and appears before her. Semi proposes to be with Yuka for seven days and do something to pay her for saving her life.
岡田惠和の脚本、山田涼介が主演を務める人間となったセミとアラサー女子のラブストーリー。羽化するために地中から出てきたセミ(山田)は、頭上から落下してきた女性・由香の下敷きになりそうになる。由香の機転でぺしゃんこの難は逃れるが、寂しそうな由香が気になり、「この人を笑顔にしたい」と願ううち、人間の姿になってしまう。
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。