The plain older sister undergoes a transformation! With her younger brother's advice, she becomes a stunning beauty that turns heads. However, the brother has harbored feelings for her since long ago... Determined not to let someone else take her away, he finally confesses his love. Though she reciprocates his feelings, she rejects him due to their sibling relationship. The brother proposes a compromise: just rubbing against each other, no penetration. But of course, things don't end there... Once they cross that line, it's a non-stop ride, with multiple rounds. Gradually, the older sister finds herself drawn to her brother as well...