A few years ago, Ayano divorced her husband and has since lived quietly with her son, Kenta. One day, Kenta is suddenly dumped by his long-term girlfriend and becomes so heartbroken he can't even eat. Seeing his distress, Ayano suggests they take a bath together, something they haven't done in years. She intends to wash away not just the dirt from their bodies, but also Kenta's lingering feelings for his ex. However, upon seeing his mother's body again after so long, Kenta feels his heart stir in ways he never expected, and soon begins harboring forbidden desires toward her. As the bond between mother and son reaches a crossroads with these new emotions, their relationship begins to take an unpredictable turn.