Aunt Chisato decides to let her nephew Kousuke stay at her home for a while to care for him after the loss of his mother. However, Chisato doesn't see Kousuke merely as someone in need of care. She is drawn to him as a man and repeatedly teases him with subtle, everyday seductions that stir his emotions. Each time, Kousuke's groin grows tense, overwhelmed by uncontrollable excitement. One night, as Chisato gently strokes his back, she begins slowly touching his body. Overcome by her warmth, Kousuke can no longer hold back, his erection growing prominent. Seeing this, Chisato smiles and takes his cock into her mouth, sharing a first kiss with him. In that moment, a new relationship begins between them.