Hiyori, a central character, endures significant personal loss following her grandmother's death, an event that profoundly impacts her. This grief manifests as prolonged, intense sorrow expressed through continuous crying. To alleviate her emotional distress, Hiyori's father creates a humanoid robot named Wasimo, meticulously designed to physically resemble the deceased grandmother. Wasimo serves as a substitute maternal figure, intended to provide comfort and ease Hiyori's suffering. The robot exhibits distinctive capabilities, including movement speeds ranging from slow paces to exceptionally rapid locomotion exceeding that of a bullet train.