Kind-hearted Machi comes across an old man collapsed on the street and begins frequently visiting his home to check on him. One day, the old man suddenly goes berserk and attacks her. Though endangered, Machi desperately fights back, beats him, and restrains him. When she consults her friends afterward, she realizes her actions could be considered criminal, plunging her into inner turmoil and fear. Realizing she must do something to erase the memory of the incident, she comes to a chilling decision.