Left widowed and struggling to raise her child alone, mother Mio faces mounting financial hardship, barely able to keep up with rent payments. A neighbor man offers help, providing temporary relief. Through this connection, Mio is asked to look after the man's son, Masaru. Unfamiliar with Mio at first, Masaru quickly becomes intensely interested in her body and gradually escalates his advances. A clingy and affection-seeking boy, Masaru enjoys touching Mio's body, repeatedly getting her to handle his cock during shared baths and forcing intimate contact in everyday situations. Initially hesitant, Mio slowly begins to experience pleasure from their encounters, eventually leading to regular sexual relations. This shocking story portrays Mio's emotional transformation and the deepening, taboo relationship with Masaru.