After her husband is injured in a traffic accident and found responsible for causing it, housewife Ririko is overwhelmed by hospital bills, treatment costs, and compensation payments. Attracted by an ad offering high hourly pay, no experience required, and only two or three shifts a week, she starts working part-time as a night guard after caring for her husband. Despite being inexperienced, she takes the job seriously. One day, a report about robbers in the area plays on the break-room television. A few days later, Ririko is suddenly assigned to work alone, and a horrifying tragedy awaits her during her patrol...