Kohtaro (Mocomichi Hayami) is a poor, struggling writer, who works mainly on mobile phone novels. He has aspirations to become a best-seller novelist, but in reality he is far from succeeding...he makes a bare living working as a freelance writer for a weekly magazine.

One day, Kohtaro's older sister Hinako (YOU), a famous and carefree actress, suddenly disappears. It seems that she has moved to Hollywood to pursue her goal. Although Hinako and Kohtaro are not blood-related, her six-year-old love child, An (Riko Yoshida), shows up on Kohtaro’s doorstep intending to stay. An is a successful child star, and her cheeky character annoys Kohtaro.

Furthermore, An's manager Mineko (Rosa Kato) reminds Kohtaro to handle their "important star" with extra care, and gives him a handbook of how to raise An. What will happen when this young man and little girl with different backgrounds, personalities and lifestyles begin to live together? This heartwarming story touches viewers as the two previously lonely characters are reminded of the warmth and affection that relationships with others can bring to them.

主人公是24岁的山下耕太郎（速水直道饰）。他的理想是成为一名小说家，可是在现实生活中，他只不过是一个贫穷的手机小说家，为了生计唯有在出版社里打工兼职。一向我行我素的耕太郎，正当享受着自己的独居生活之时，一天他的姐姐突然无故失踪。在迫不得已的情况下，耕太郎只好让姐姐的私生女儿，即6岁的著名童星- 杏（吉田里琴饰） 住进自己的家中。没个大人样的的耕太郎经常被少年老成的杏捉弄。

另一方面，杏的经理人峰子（加藤罗沙饰），给了耕太郎一本如何与杏一起生活的指南。并警告耕太郎千万不要伤害杏这么重要的「商品」。到底两个年龄、性格完全不同的人，生活在同一屋檐下，对他们的成长及思想有什么的影响呢？

这是一部探索人与人之间关系的温情剧集。