Manami Oura begins living with her elderly father-in-law to care for him, but his worsening senility leads to more trouble than expected. Accidentally ingesting her impotent husband's hidden erection medication, she suddenly cries out, "My cock is in pain!" and reluctantly performs emergency relief with her hands and mouth. At night, he eats large amounts of pickles, complains of thirst, and demands, "Give me some moisture!" seeking tongue kisses and cunnilingus. Despite his confused mind, her father-in-law's cock remains constantly erect, driven by intense desire for Manami's youthful body. Though initially hesitant about this long-absent intimacy, Manami gradually finds herself drawn to his passionate advances.