Because Duri is so busy having fun during his summer break he doesn’t have enough time to do any of his homework, so he asks Tayo for help.
But, Tayo is too busy to help so he asks Rogi to help Duri. Rogi tries his best to help Duri's homeowrk, but ends up making a mess of everything.
Duri is very disappointed. He tells Rogi that Tayo would have done a much better job. This inspires Rogi to work much harder and fix all the mistakes he made.