Sumire had two sons. Kiyo, her own son, and Takeru, her husband's stepchild. Sumire thought she loved Takeru as if he were her own child, but Takeru's situation was different. Takeru was in his prime and at an age where he was greedy for sex. One day, Takeru, who was interested in Sumire's large breasts, took advantage of their relationship and asked Sumire to show him her breasts. Sumire was reluctant, but since it was his son's request, she exposed her breasts and let him touch them. In fact, Kiyo had been watching the whole thing! Jealous, Kiyo began making unreasonable sexual demands on Sumire...