To Tsukishima Ren, his sister was always a mystery. Five years older, Sumire lived her life at a distance, both emotionally and physically, leaving Ren in a home fractured by their mother's absence and a father's quiet despair. Now, after Sumire's sudden death, Ren is left to grapple with the complex emotions of mourning someone who felt more like a stranger than family. As he revisits fragmented memories-of her carefree smiles, unfinished manuscripts, and the painful distance between them-Ren finds himself lost in a storm of unresolved feelings. In a narrative filled with raw reflections, quiet anger, and a longing to understand the person his sister truly was, Ren must confront the question: Can you grieve for someone you never really knew?