周繼薇本來應該叫做「周繼偉」，是老媽一雪前恥的希望！

但，當她呱呱落地之後，希望幻滅了，她那被賦予獨一無二的「貴子」命運，卻瞬間變成了「周家第三個女兒」。所以她只能穿前頭兩個姊姊的舊衣服、暗暗嚮往著永遠分不到的魚眼睛――因為一隻魚只有兩隻眼睛、一隻雞也只有兩隻腿，因此「第三個」的意思，就是多出來的那個。

但，多出來的周繼薇，卻深獲鄰居戴奶奶的喜愛，於是，她總是離家出走、直奔戴家的懷抱。在好乾淨、好舒服的戴家，她是一個被愛包圍的小公主，還有一個帥氣的小哥哥「戴耀起」――雖然，戴耀起根本不想有一個妹妹來跟他分食人間美味「魚眼睛」。

想盡辦法要變成戴耀起的妹妹的周繼薇，終於在17歲那年，發現了一個連自己都不知道的秘密――她不需要永恆、也不需要美麗的愛情樣子，她只想要永遠跟戴耀起「一起」。

The Zhou family has high hopes in giving birth to a son but was disappointed when Zhou Jiwei was born a girl, making her the third daughter in line. Because she was a disappointment to the family, she was only ever given hand me downs from her sisters. She felt no love from her family, but luckily she feels the love of a family from her neighbours. There she meets her 'brother' Dai Yaoqi and follows him around trying to be the best sister ever, however, he has never wanted to have a sister. As she tries her best to be close to him as his sister, she slowly realizes the feelings she holds for him are not love for a brother but something more.