Akira, a student preparing for entrance exams, was having trouble concentrating. Even if he wanted to continue studying, his concentration quickly waned and he started thinking about naughty things. Akira was troubled by such worldly desires, but today, by chance, his mother's best friend Yumiko came to visit. Seeing Yumiko's voluptuous cleavage, Akira's worldly desires swelled even more. Unable to hold back, he locked himself in his room and was masturbating when suddenly Yumiko came in...