The episode starts with Shishimaru skulking around the house in the morning. Later on, Hattori, Shinzo, Shishimaru and Kenichi take Kenichi's model plane to the waste ground to fly it to impress Yumeko. Suddenly, Kemumaki comes with his top-of-the-range remote controlled plane and shows off by flying it. He then gives Yumeko a turn, but she accidentally crashes into Kenichi's plane. Upset and angry at his plane's destruction, Kenichi storms back to his house. Hattori, Shinzo and Shishimaru then follow him.
Unfortunately, Mr and Mrs Mitsuba refuse to buy Kenichi another model plane, because they assume that he is copying Kemumaki, and Kenichi has a go at a hurt and bewildered Yumeko. Hattori, on the other hand, decides to solve the problem by building a one - off lightweight aircraft for Kenichi and tells him to jog to power his legs. However, the plane refuses to take off, leading to Shinzo crying. This gives Hattori an idea.
Hattori straps Shinzo to the back of the plane, amid Shinzo's many apologies. When Hattori then punches Shinzo over the head, Yumeko appears out of nowhere and tells Hattori off for assaulting his brother. Shinzo, upset over Yumeko's anger, bursts into noisy tears and the plane takes off. However, Kenichi worries that the plane will crash if Shinzo's crying stops.