Late one night, Kenichi reads a book on manliness. He resolves to act like a man at least for tomorrow. The following day, Kenichi hurries while eating his breakfast. Mrs Mitsuba persuades him to calm down, and Kenichi remembers a line in the book he had been reading the previous night. He then thanks God for his breakfast and marches off, chanting, "If you are a man, behave like a man!"
As he marches along, a police officer tells him to hurry to school. Kenichi tells him that a man never loses his head, and continues on his journey. At school, Mr Koike is teaching geometry, when Kenichi barges in. He says a loud good morning to the class - only to get shouted at by Mr Koike. Kenichi tells him that a man never gets angry over trivial things. Meanwhile, Yumeko tells Kemumaki that Kenichi is acting oddly. Kemumaki sniggers that Kenichi always comes up with crazy ideas like that...
At homework distribution, Kenichi tells Mr Koike that he forgot to do his homework. As punishment, Kenichi is forced to walk ten times around the school building, and he's OK with that.
On the way home, Kenichi bellows his anthem out loud to the street. Kemumaki tells Yumeko that he's worried about Kenichi, but Yumeko tells him that she likes his attitude.
Kenichi reaches home and praises Hattori, Shinzo and Shishimaru for their good ninja performance. Hattori persuades Shinzo and Shishimaru to join Kenichi, and they go to an ice cream parlour. Kenichi, having bought three ice creams, two for Shinzo and one for Shishimaru, says that a man is always generous. Meanwhile, Kemumaki and Kagechiyo, who have been spying on them, try to lure him to a girl...
At the park, Kenichi and Yumeko are brought together. Kemumaki tries to use a perfume to make Kenichi act like a girl, winking and sending a heart towards Kenichi. However, Hattori, hiding, makes it hit Kemumaki, who goes all girly. Kenichi then rebukes him, and he runs off in tears. Kenichi tells a puzzled Yumeko that a man should always be a man.