There used to be a family of four living in a certain housing complex. The father who is a businessman, the mother who is working as a part-time cashier at a supermarket, the 9 year-old elder daughter Yuuna, and the 4 year-old younger daughter Naho. On a certain morning in the early summer just before everybody takes summer break, encouraged by her mother, Yuuna prepares a bento box lunch for her family for the first time in her life. She challenges herself to make rolled omelet and packs vegetables and sausages in the boxes. Her father and mother are very proud of their daughter's growth. During breakfast, the mother asks the father a favor, but the conversation leads to a discussion about the financial situation that concerns their daughters' future. Their opinions conflict, and the conversation escalates into a big argument. Meanwhile, Yuuna encourages herself to take a certain action.