For two years while her husband was away on a solo work assignment, Sachiko developed an intimate relationship with her only son. Beyond the blood tie of being mother and child, they became deeply connected in both mind and body. Though she knows it's wrong, she can't bear the loneliness and finds herself drawn further into the relationship. Obsessed with the intense sex they share, she becomes completely addicted to the pleasure. Even after her husband returns home, the affair continues in secret, and now she looks forward to the days when her husband goes out. A forbidden relationship entwined with love and desire, driven by deep loneliness and raw impulse.