In a world where everyone is born genderless until they choose to be male or female at 12 years old, things get complicated for a 17-year-old who still hasn’t decided in this coming-of-age drama.

In this world, when a person reaches 12 years of age, their body begins to change depending on the gender they wish to become. By 14, they'll complete their transition. However, Hinase, a high school senior about to turn 18, is still undecided. How will this affect Hinase’s future and potential romantic relationships?