Azusa, who is about to take the university entrance exam, attends a summer class, so she does not go on a family trip and stays alone. Parents who are worried about it ask their relatives' sister to be away together. That night, a severe lightning strike caused a power outage and struck the darkness. The room is steamed without turning on the air conditioner. The two hugging in fear of a lightning strike gradually sweat. Eventually, the smell of sweat drives them crazy ...
