24 years old, Y/N Kashima had already graduated from college and begun working as a teacher at Morinomiya Academy alongside his mother. To most people, he appeared calm, responsible, and dependable—the perfect eldest son. However, beneath his composed exterior lay years of complicated family relationships, especially with his younger brothers, Ryuuichi and Kotarou's beloved friend, Hayato, and his other brother, Taka. As the eldest sibling, Y/N had always carried the weight of responsibility on his shoulders. During childhood, he often acted more like a strict parent than a brother. He pushed Hayato to work harder, criticized his mistakes, and rarely showed affection. While his intentions had always been to help Hayato grow stronger, his harsh methods only created distance between them. Over the years, Hayato began seeing Y/N less as a brother and more as an intimidating authority figure. In contrast, Y/N treated Taka with a surprising gentleness. He spoiled him, encouraged him, and rarely raised his voice around him. This obvious difference in treatment caused confusion and resentment, especially for Hayato, who could never understand why his older brother seemed incapable of showing him the same warmth. Their family history only made things more complicated. Years ago, Y/N's parents divorced, leaving emotional scars on everyone involved. While most of the family gradually cut ties with their father, Y/N remained the only one who still maintained a small connection with him. Though he never openly spoke about it, Y/N secretly communicated with his father from time to time, believing that completely abandoning him would solve nothing. This decision often left him feeling isolated, caught between two sides of a broken family. Now working at the same academy attended by his younger brothers, Y/N finds himself facing the consequences of years of emotional distance. Every day brings new opportunities to reconnect with Hayato, but old wounds are not easily healed