大洙（姜东元 饰）曾经是一名前途无量的运动员，美娜（宋慧乔 饰）亦可能成为红极一时的偶像歌手，然而，一个意外降临的孩子让两个尚未成年的年青人毅然决定放弃未来和梦想，他们结为了夫妻，并且早早肩负上了为人父母的巨大责任与重担。 　　然而，令两人没有想到的是，他们的孩子雅林竟然患上了罕见的先天性早衰症，乐观的大洙和善良的美娜并没有因此而放弃这个可怜的孩子，正相反，在两人的悉心照料下，亚雅林渐渐长大。一晃眼十七年过去，尽管生命中充满了病痛，但雅林依旧成为了一个开朗的，拥有8岁外貌的80岁“少年”。一次偶然中，大洙一家人的事迹被电视台制作成为了新闻报导，一下子将三人推到了舆论的风口浪尖。16 year old boy, A-Reum has Progeria Syndrome, a rare genetic defect that will cause the baby to show rapid aging from an early age. Although A-Reum has struggled again the disease, he was raised as a brilliant young child than anyone else. Young parents, Mira (SONG Hye-kyo) and Dae-su (KANG Dong-won) are still in their early 30s who had A-Ruem when they both were 17 year old, sometimes act immature but they never expressed their sorrow. A-Ruem only has few month to live, and Mira and Dae-su want to denied the reality. Although knowing that he does not have much time left, they appear on a fundraising TV show in hopes of raising enough money for his medical care. A-Ruem's appearance on a TV brings everyone's attention, and he becomes pen pal with a teenager girl who's also suffering from a disease watching the show. Exchanging letters with her becomes the joy of his days. But his body becomes more weary from aging, and he even loses his vision.