He accidentally slapped his stepson for 'seducing' him, and his stepmother apologized in the best way possible. Since his father remarried Yu, Ryota gained a stepmother. Ryota is at an age where he is exploring 'sexual' issues, and his stepmother is incredibly beautiful and alluring, her smile seems to draw his soul away. Despite that, Yu is his father's wife, and Ryota has given up, knowing his feelings will not be reciprocated. Unexpectedly, an opportunity arises. His father will be on a business trip for three days, and Ryota will not miss this unique chance! He then attacks Yu to take her for himself! But Yu strongly resists and slaps him. Realizing she overreacted, that night Yu went to Ryota's room to make amends with him. Ryota agrees to forgive Yu on one condition: she must close her eyes. He uses this opportunity to take her again! But unlike before, this time Yu resists less, as if she is allowing Ryota to take over her body. The pleasure Ryota brings her quickly conquers her. Although she knew this was wrong, Yu couldn't stop. She wanted to be with Ryota even more. The two continued to be intimate throughout the time her father was on a business trip, and even after he returned, they maintained their forbidden relationship...