Mizuhara Sana lost her husband at a young age and raised two sons on her own. The elder brother, Koichi, is quiet, while the younger brother, Yuji, is spoiled. Though their personalities are complete opposites, both grew up healthy and are her pride and joy. However, Yuji still hasn't weaned from his mother's breast and lacks sexual knowledge. Sana teaches him handjobs and blowjobs under the guise of education, but when Koichi finds out, he too starts demanding her body. Before long, the brothers start fighting over Sana, so to avoid conflict, she proposes a taboo threesome with her sons.
