Eun Guk and Eun Soo are siblings living alone after their father passed away. Eun Guk works at the post office. He feels like he is getting older, because of his younger sister's behavior like skipping school to attend an audition. Meanwhile, Eun Soo thinks her life is weary even though she is only 10 years old. She thinks that because of her older brother, she can't pursue her dreams.