Morino Hotaru is a second year high school student who has had an unrequited crush on Otaka Ren since junior high school. One day, while on a school trip with Ren and her good friend Yamamoto Shiori, their bus gets into an accident. When Hotaru wakes up, a young man who is dressed fully in black appears in front of her. He is Kuro, a grim reaper. A shocked Hotaru shoves him away but he has shocking words for her, “I’m your guide. Morino Hotaru, listen carefully. You’re dead.” Hotaru learns that if she does not get over her attachment to three things within 49 days, she will end up becoming a ghost bound to a specific physical location and cannot rest in peace.