For three years attending a boarding school, he had lived a fulfilling student life, and finally graduation day had arrived. Throughout those days, the one who had supported him was Airi, his stepmother and also someone he had long admired. Filled with gratitude, he was shocked when he suddenly received word that she couldn't attend the graduation ceremony. Yet on that day, he spotted a familiar figure waving at him with a smile from across the street—Airi herself. Overcome with emotion by her warm, gentle presence, he joyfully made a promise with her to celebrate his graduation together tonight. In that moment, his heart was stirred by an unexpected, profound feeling.