Hiromi Ishimaru has nothing but fond childhood memories of her cousin Makoto Kashiwagi, so she is ecstatic to find out that he is moving from the country to live with her. However, when Hiromi meets Makoto again after nearly nine years, the last thing she expected is for him to have F-cup breasts! It turns out that Makoto, or "Mako," is intersex, meaning she has the sexual characteristics of both males and females. While this proves to make Mako's dating life difficult, Hiromi tries her best to help her cousin out when she needs it.

[Written by MAL Rewrite]