With an ailing mother and a very busy father, Da-yi is used to doing everything by himself. His family moves closer to his mother's hospital so Da-yi can visit his mother every day. Though in new neighborhood and school, Da-yi does not feel lonely as long as he is with his mother. He visits his mother every day to spend time with her. Gradually adjusting to his new school, Da-yi becomes best friends with his classmates Yu-jin and Min-ho. As he spends more time with his friends, he spends less time thinking about his mother. However, when his mother's condition worsens and she is transferred to a faraway hospital, Da-yi gets worried that he may never see her again and heads out on the search with his friends.