Mako Koyuri, trying to lose weight, has recently taken up nighttime jogging. While running, she becomes increasingly frightened by a strange, unsettling gaze she feels from behind. When she tells her family, no one takes her seriously, deepening her anxiety. One day, while jogging as usual, she is suddenly attacked. She desperately tries to escape, managing to break free after yanking her assailant's hand. However, several days later, the same terrifying ordeal begins to unfold once again.