Hattori, Shinzo, Shishimaru and Kenichi face a lot of chaos while accompanying their matriarch on a road trip while Mrs Mitsuba is driving after passing her driving test.
Kenichi and Shinzo are bickering about Kenichi's broken golf club when Mrs Mitsuba turns up, showing her driving licence off. She then tells everyone to get in the car so that they can get a new golf club for Kenichi. Later on, Mrs Mitsuba, Kenichi, Hattori, Shinzo and Shishimaru are in the car, fastening their seatbelts. They set off at a bouncy ride. Kenichi is concerned about his mother, but Mrs Mitsuba tells him to shut his face. They then get stuck in traffic. Shinzo scorns his foster mother - only to make her shout like she never shouted before. The car starts to fall downhill and nearly crashes into a vintage Rolls-Royce. Then the engine overheats because the car was in first gear. Mrs Mitsuba then storms out of the car.
Kentaru then gets fined 2,000 Yen which results in a severe argument between himself and Mrs Mitsuba. Mrs Mitsuba blames Kentaru for owning a "useless" car while Mr Mitsuba fiercely replies that he lost a lot of money. Mrs Mitsuba then dissolves in tears and says that her friends' husbands do not treat their wives like Kentaru just treated her. Hattori is shocked by this. He then informs the gang of this problem. While Shinzo and Kenichi say that Mrs Mitsuba deserved it, Hattori fiercely maintains that it was not Mrs Mitsuba's fault, and it was wrong of the gang to think that she was bad. They then try to find their matriarch and apologise to her. The bad news is that they don't technically find her. The good news is that Mrs Mitsuba and Mr Mitsuba have stopped arguing and are happily learning about how the gearbox works. Hattori and the gang are ecstatic by this.