Hinami and Rui are cousins. Both only children, they have been close like sisters since they were little. The two have had various experiences and have established their sexual preferences. Rui is obsessed with sex, regardless of gender, while Hinami has had no luck with men and has become fed up with them. Before she knows it, she has begun to long for the world of yuri. Rui gradually invites Hinami into the world of yuri.