Satoshi visits the Harada family for the first time in a long while to see his uncle, who he's been close to since childhood. However, as soon as he arrives at the house, a man in a suit comes out of the entrance. It seems he has to leave on a sudden business trip. "Mina, leave Satoshi in charge," the uncle tells his wife as he hurriedly leaves. Satoshi is left behind to spend the weekend alone with his aunt Mina, and is taken aback by this unexpected turn of events. And then, an incident occurs...