Young-ho doesn't have any dreams for his life. He has been studying for three years to enter a university. He decides to send a letter to his childhood friend So-yeon. But her younger sister So-hee receives the letter instead of her sick sister. So-hee writes back to Young-ho, pretending to be So-yeon. Meanwhile, So-hee takes care of her sick sister and also runs a secondhand bookstore with her mother.
Elenco: Kang Ha-neul , Chun Woo-hee , Kang So-ra , Lee Sul , Lim Ju-hwan , Lee Hang-na , Lee Yang-hee , Park Se-hyun , Kim Sung-kyun , Go Geon-han , Nam Hyun-woo , Kim Min-seo , Kang Yeong-seok , Go U-rim , Choi Myeong-bin , Won Ji-u .