Mahiru, a younger sister who harbors deep admiration for her older sister. Azusa, the elder sister, becomes aware of these feelings and cherishes her sister in return. From one day forward, their bond evolves into adult emotions, crossing forbidden boundaries. I want to satisfy my big sister. I want to give my little sister the ultimate pleasure. Intertwined tongues, tightly pressed positions, deep loving with strapon fucking. The sisters' love grows bright yet profound, breaking down the walls of taboo.