Dennis is determined to get a horse for Christmas, So on Christmas day he goes around the neighborhood trying to find what he thinks is his horse.

Dennis convinces Mr. Wilson to run for park commissioner because the playgroung is closed except on weekends.

Mr. Wilson takes Dennis and his friends to a camp to visit for a day and end up getting stranded there for a week because a bridge went out due to a storm.

Dennis overhears Mr. Wilson saying that he wishes he had his racoon coat back, so he gives the story to the newspaper and so all day people are bringing Mr. Wilson racoon coats.

Dennis writes a composition for school on his best friend and he chooses Mr. Wilson to write about.

Dennis accidently steps on one of Mr. Wilson's plants and so he buys him a replacement and plants it in Mr. Wilson's flower bed. When Mr. Wilson sees it, he is convinced that his new miracle plant food that he invented works like a miracle.

Dennis gets an electric car for his mom from the lady who won the Raffle.

Dennis attempts to find Miss. Cathcart a best friend, so he gets her a dog from the pound. However the dog's owner is looking for him and ends up showing up at Miss. Cathcart's house before Dennis brings the dog over to Miss. Cathcart. So she mistakenly thinks that the guy is the friend instead of the dog.

Miss Cathcart's cat is accidentally locked in the trunk of Mr. Wilson's car.

Mr. Wilson has a hundred doller bill which he drops and a crow picks it up and flies away with it. He later finds it in an old tree in a park which the park commissioner is going to cut down, So Mr. Wilson climbs the tree to get his hundred doller bill and to also save the tree from being cut down.

Mr. Wilson builds a barbecue in his backyard with help from Dennis' friend, Fred Bains.

Dennis enters a soapbox derby and Mr. Wilson accidently ends up being the one driving it in the race.

Mr. Wilson is supposed to take a picture of a plant that bloomes at night but ends up dozing off when it bloomes, So Dennis takes the picture of the plant for him.

Mr. Wilson gives Dennis an old radio set that he mistakenly bid for at an auction. However, When Dennis finds money in his radio set, Mr. Wilson gets excited. So him and Mitchell put in add in the paper hoping the real owner isn't around to claim it.

Tommy has a saxophone that he doesn't want so Dennis wants to buy it from Tommy's Mother, but when Mr. Wilson learns that Dennis is going to ask his father to buy it for him Mr. Wilson tries to talk Dennis's dad out of getting the saxophone.

Dennis gets his mom a going away present and hides it on Mr. Wilson's closet shelf and Mrs. Wilson finds it and thinks it's a gift from Mr. Wilson.

Dennis attempts to buy a fishing rod for his dad and tries to purchase it with a $50.00 Confederate bill.

Dennis brings home little chicken eggs to take care of for his school project, but ends up taking them over to Mr. Wilson's house because the Mitchell's electricity went out.

Mr. Wilson has a stock certificate worth $500. He hides it in his Phone book, however when Dennis brings him in his new phone book Mr. Wilson goes crazy and ends up going to the warehouse where all the old phonebooks are taken to look for his old phone book because he thinks the stock is still in it.

Dennis tries to take care of his mom because she is sick and his dad is out of town.

Dennis starts a rock collection and ends up finding what he thinks is real gold on Mr. Wilson's lot

Dennis wants to help out for Paint-up, Clean-up week. So Mr. Wilson gives Dennis a bucket of red paint to paint his wagon with. Dennis however also decides to paint the street curve by Mr. Wilson's house and Mr. Wilson gets blamed for it.

Dennis accidently knocks over a bottle which fumigates the Wilson's house, So the Wilson's stay the night at the Mitchell's and Mr. Wilson walks in his sleep.

Mr. Wilson puts on a magic show for Dennis' birthday and asks Spring Byington to be his assistant

Mr. Wilson's Niece is getting married and asks Dennis to be the ring bear.