A hot spring trip taken with her two sons while leaving her husband at home. Feeling the liberating atmosphere of travel, the two gradually grow close like lovers along the way, drawing near each other until their suppressed emotions erupt. At the outdoor bath of their lodging, feelings they can no longer hide begin to surface, deepening their intense mother-son relationship. Step by step, they cross the boundaries of societal norms. Their desire grows stronger without restraint, and as night deepens, they begin walking a path from which there is no return.