Kururugi Subaru, a dedicated employee in an apparel company, leads an innovative brand project alongside his colleagues Andou Keita and Shitou Sae. Aoi Seina, a fresh-faced newcomer, joins their team, and Subaru finds himself falling for her. After a year of growing fondness, he confesses his feelings, leading to a blossoming romance and eventual marriage. Seina changes her last name and transfers departments to maintain professional boundaries, but they still cherish their shared lunch breaks as newlyweds. When Seina receives an invitation to a class reunion, she initially declines, citing her busy work and home life. However, Subaru encourages her to attend, not wanting her to feel constrained. His coworker, Keita, playfully teases him about the possibility of Seina encountering an ex-boyfriend, planting a seed of anxiety in Subaru's mind. Seina returns from the reunion with souvenirs, appearing normal at first. Subaru feels relieved, believing Keita's comment was off-base. Yet, he soon notices subtle changes in Seina's behavior. She seems occasionally lost in thought, leaving Subaru concerned. He longs to offer support, but the lingering memory of Keita's words and his own insecurities prevent him from initiating a conversation.