It's sports day at school - but Kenichi has forgotten his cheering flag. Cue Hattori and the gang to the rescue!
Mrs Mitsuba gives Kenichi his cheering flag for the sports day, and firmly warns him not to lose it. Kenichi, however, leaves it at home. When he finds out that it isn't there, Yumeko and the other girls are crestfallen, while Kemumaki pokes fun at poor old Kenichi. Kenichi frantically calls his house, hoping to speak to Hattori, but Shinzo picks up instead, and tells Kenichi that Hattori is in a weakened state after he had an accident during his training. The scene then reverts to Hattori staggering out of the living room and collapsing, his face covered in cuts. Back to the telephone scene Shinzo, promises that he and Shishimaru will deliver the flag by five past twelve in the afternoon.
Shinzo and Shishimaru dash out, carrying the flag with them. They then hear a voice, and find Kagechiyo the cat, apparently drowning the river. They rush to his aid - but then they realise it was a trick! They then retrieve the flag, capture Kagechiyo, and take them back home. They are then slowed down by Hattori, whose health has improved slightly. He then manages to climb onto the roof of the house, and sends the flag in the air, it being a windy day. He is pleased to see that his plan has worked - but he is blown by the wind and is sent backwards into a tree.
Meanwhile, the school frets about the missing flag, when lo and behold, the flag appears in the sky. They retrieve it somehow, and they celebrate. Kemumaki joins in, albeit grudgingly.
Back near the neighbourhood, Hattori is having trouble getting down the tree, having been more seriously injured.