By a strange twist of fate, sister "Koharu" ends up kissing her older brother. Her lolita-obsessed, sister-fixated brother becomes captivated by Koharu's soft lips, overwhelmed by uncontrollable desire. Skillfully seducing the pure and obedient Koharu, he begins performing lewd acts on his adorable little sister. Having suppressed his longing for so long, the brother's passion finally explodes, surpassing his limits and beginning a new, forbidden relationship.