Mom is a great detective!?

Today is payday for Hiroshi's mother, Hiroko, who works part-time. Hiroko stops by her department store and witnesses the moment of Matenro's crime, and immediately after that, Dr. Ochiai. As expected, Matenro is Ochiai-sensei!? Meanwhile, Hiroshi and his friends are concerned about Matenro's recent movements. Perhaps he plans to earn some money and flee overseas soon?