On their way to the museum, the Man with the Yellow Hat and George discover that Gnocchi the cat has been accused of scratching the booths in Chef Pisghetti's restaurant. George isn't sure that it was Gnocchi and sets out to solve the mystery. George uses reasoning to find out that the scratches he had seen on the booths were not like scratches he had seen Gnocchi make on the door and he uses pieces of food to measure the length and depth of the scratches.

George has found himself a new friend in the city, Compass. One of the Doorman's homing pigeons which he keeps on the roof of the apartment building. But the only thing is, Compass has a bad sense of direction. So when the Man says George is not allowed to let pigeons inside the apartment, George decides to build Compass a new home on the balcony outside their apartment, eventually deciding on a tree. But soon George finds out building a tree is not as easy as it seems. Where do trees in nature come from if people don't make them?

One day George is walking the street of his apartment building trying to find something to do when he notices a woman leaving numbered boxes outside every building. He decides to be a helpful monkey and return them to her until his friends Steve & Betsy tell him that she is a postal worker and that leaving boxes for people is her job. So they go on a race to see who can finish returning packages first. Winner plays Steve's video game. Steve has a plan to simply run fast but George and Betsy come up with a plan to sort all of the packages by the number of the buildings they go to.

On a sunny city Saturday, George and the Man decide that it is a good day for donuts and eggs. The Man tells George to write down the number of eggs they have in the refrigerator but George does not write anything because they had none. The Man then realizes that after teaching George everything for so long he forgot to teach him about nothing! He says that zero alone means nothing but when added to smaller numbers makes them bigger. The Man then sends George off to get the donuts with a paper that has an order of 1 Dozen Donuts. But George does not know about a dozen and changes the order to 100 dozen donuts. But after seeing just how many donuts 100 dozen make he tries to do anything to get away with only 1 dozen.

George and The Man have just brought home a new rug. The Man thinks it is so perfect he would like to take a picture of it. But when he runs out to get some camera batteries George decides to have a drink of grape juice and spills it on the rug! George knows how to clean it up, though—a lot of soap and water. But he uses so much he fills up the whole house with suds and water. Luckily he knows about the time his friends The Renkins' basement got flooded and they cleaned it out with a pump. George finds the pump at their house but has no easy way to get it back home.

George is off to the country boat building contest but on the way, he sees something interesting: a boat that carries cars on the water. Bill shows George his boat and has him watch it for him while he has to run off. But when an accident causes Bill's boat to sink and is no longer able to float, George has to build him a new one so he can use it in the contest instead. But all of the boats George build seem to have the same problem. So he decides to look at how the boats made by the other contestants were built so he can build one that floats.

The owners of the local city toy store have a problem. They are not selling any roller skates. So when they see George they decide to give him a few pairs to ride around in and advertise for them. Fortunately, George has been curious about wheels on feet since he saw the man roll on a toy car. George loves his skates but realizes he needs practice. He is getting good when the Doorman's wiener dog Hundley sees that he would like to try it as well. Later on, Gnocchi also tries out roller skating and uses Hundley as her skateboard when she sees kids doing it at the local skatepark.

George's friend Professor Wiseman has a pretty interesting habit-building and fixing clocks. She has just finished work on a very interesting clock where a band comes out and plays every hour. But when Compass comes flying in and George tries to show him the clock he accidentally breaks it and then winds up taking it completely apart when he tries to fix it. George goes to the library to try to find out how to fix it but not from a book. The library has a big clock tower on top that the whole city depends upon. But when the clock's chime scares George he winds up breaking the big clock as well.

George is in the country seeing Bill's new bunny hutch. Bill is the proud owner of six bunnies and their rabbit mother. George wants to pet one of the bunnies but Bill has to run off on his paper route before he can let him do that. George tries to pet one but when he opens the hutch they all run off leaving George in a big game of hide and seek to find them all.