Ever since childhood, she has looked up to her cousin Mao Hamasaki like an older sister. As the years passed, her feelings evolved into a deep emotional dependence. Mao is openly lesbian, having come out at 18, and now freely enjoys romantic and sexual relationships with women. To her, Mao is a uniquely special person, and while she finds herself drawn to the idea of such intimacy, she struggles to understand her own emotions. As their bond gradually deepens, she begins to see Mao in a new, more profound light. This story follows the evolving relationship between them and the intimate journey they embark on together.