"Nao alone?" A long-awaited return to her hometown, a long-awaited reunion, a summer vacation, a girl looking forward to spending time with her beloved uncle. Her uncle is also looking forward to seeing his niece, who has become a high school student, grow up. Her sleeping figure is too dazzling, her chest is open... Her uncle senses the "woman" in his napping niece and makes a move on her... Seduces his childhood friend. And sex... Through various summer experiences, Nao grows rapidly from a girl to an adult "woman".