Miya's relationship with her husband had deteriorated. Perhaps they were incompatible—sexual intimacy had long disappeared, and she grew to hate everything about her life. She was exceptionally close to her son, Takuya, and people around them often referred to them as "friends-like mother and son." One day, almost naturally, they began a sexual relationship, and since then, they've continued their affair in secret, careful to avoid her husband's eyes. With no reservations, they freely indulged in their desires. Now, wanting to take their pleasure to a deeper level, they secretly set off on a journey together.