After her husband left home for having an affair, Mio pretended to be strong in front of her son, but spent her nights masturbating to ease her loneliness. This went on for so long that she finally felt she had reached her limit. When she realized her son was stepping into forbidden territory, driven by a desire to comfort her, Mio resolved to accept it as a mother. However, her son, who had inherited her own strong libido, turned out to be a stamina monster capable of endless rounds. As Mio's emotions and her son's lust intertwine, a new relationship begins.