Susumu can't hide his dissatisfaction when his parents force him to take care of a greengrocer. He announces to Ochiai Sensei, who has just visited his shop, that he will spend the weekend in the mountains practicing ninjutsu. When Ochiai heard this, he advised him, "Find your true courage in the mountains." Susumu set off with a bang, but Mt. Kiribuki, which is known for its thick fog, is still a scary place for Susumu...