Kenichi is often bullied at school, which is why he always falls into a state of depression, suffering every time he starts a new day. During this time, Kenichi's aunt Mary left her home and went to stay with him. It turns out that her husband was too focused on work, and they hadn't been intimate in a long time, which led to Mary arguing with her husband and leaving. In the past, Kenichi and Mary were very close to each other, and they often took baths together. While preparing to take a bath, Mary suddenly heard Kenichi crying. Wanting to comfort him, she decided to bathe her beloved nephew just like before. But now Kenichi had grown into a tall young man, and of course, his private parts were very large, even larger than her husband’s! Mary argued with her husband due to a lack of intimacy, so when she saw Kenichi's genitals, her arousal rose and crossed the final boundary...