The story of a tutor and Yuna's blue eros. The tutor was worried about Yuna's recent actions. Every time she took her lessons, she felt she was seducing herself with her healthy body. Yuna who takes classes without wearing her underwear and has a fearless smile, and also asks sexual questions such as "Are you doing sex alone?" "When did you have sex?" .. And Yuna invites her weak tutor to her forbidden Eros ...