One day, Hira Katsuki, a part-timer living a listless life, picked up what looked like a runaway girl. The girl who called herself Mayu was standing there with a sign hanging from her neck that read, “Please pick me up.” Though thinking it as troublesome, Katsuki allows her to stay in his home apartment for only one week, as he worried she might get caught up in a crime. She is a girl who won’t reply at all when asked about the details of her running away from home, however, the distance between them gets closer little by little–. And then the promised seventh day is approaching!?