Yui was asked by a client's company president, to whom she owes a debt of gratitude, to take care of his nephew, Komomo and Chinta. However, Chinta turned out to be a far more precocious brat than she expected. Though Yui normally carries herself confidently as a strong-willed company president, she finds herself flustered by Chinta's mischievous antics. When he starts acting clingy, she ends up bathing with him, where he proudly displays his fully erect cock, making her increasingly aroused despite herself. Living together with an adult woman drives Chinta into a constant state of excitement, and he secretly demands sexual relief from her inside the office. Their relationship quickly escalates, and Yui, who had been sexually frustrated all along, gradually finds herself drawn to his cock.