Widowed Waka lives alone with her late husband's child. In truth, the two have long been aware of each other as romantic interests. Once before, they committed a mistake together. The time that had stood still since then begins to move again during a hot spring trip for two. The son makes advances toward his mother. Though she feels it's wrong, she accepts him as if she had been waiting for this. Her secret vessel grows wet from her son's caresses. She climaxes as his erect dick is inserted inside her. The barrier of parent and child crumbles, and they seek each other out, intertwining again and again in this forbidden incest story.