Episode 12: If You Don't Like Worrying...

Onui is concerned for Shunpei having to worry about his mistakes in his calculations. The old man tells the story about Naje-Naje, a curious boy who, after pestering the villagers with questions, sets on a dangerous journey to seek the answer to the ultimate question, though the old man leaves it as a cliffhanger. Shunpei goes out with Onui to ask various residents about his stress, but to no avail. The next day, the two talk to Toyama, Oise, and Oriku, yet they were no help either. Shunpei reminisces of when he used to play with a dog as a child. He wished to be able to run away with her when his parents were fighting, but needed to stay because he wanted to solve a math problem. It is implied that Onui was the dog from Shunpei's childhood.