In the bustling halls of a Seoul high school, Kang Iseul is a quiet outcast haunted by the memory of her deceased brother. Her world shifts when the charming exchange student, Taehyung, arrives, bearing an uncanny resemblance to her lost sibling. As she begins to form a bond with him, Iseul's unease grows when another student, the popular and enigmatic Jungkook, starts showing an interest in her. With secrets lurking in the shadows, Iseul must navigate the complexities of friendship, betrayal, and the lingering pain of her past, all while uncovering the truth behind her brother's death.