Mr. Wilson's former employers offer him an executive position at his old company, but it will require him to relocate to Pittsburgh, PA. Dennis doesn't want him to go, but when Mr. Wilson decides to take the job, Dennis blames himself and runs away from home.

Mr. Wilson is nervous about hosting his niece's upcoming wedding, especially with Dennis as the ringbearer.

While watching an auction from the sidewalk, Dennis causes Mr Wilson to raise his hand when an old-fashioned radio is being auctioned. George has to pay for it since it appeared to be a bid. Turns out the radio has a hidden stack of money.

One of Dennis' friends gives him a pet in a cage that he says is a hamster. The animal escapes from the cage, and everyone finds out it is really a gopher when Mr Wilson's yard is nearly destroyed.

When George gives away books, he includes a book that holds a stock certificate worth $500. He tries to get the book back, but it is too late. Dennis saves the day when he realizes he found the stock and kept it because it looked neat!

With his father away on a business trip and his mother sick in bed with a cold, Dennis has to be the "man of the house". This includes doing laundry with Margaret's help, and arranging a dinner party with his friends in connection with a sales pitch.

Dennis starts collecting rocks to build a collection. He finds some rocks that he thinks are real gold.

Henry has plans to play golf, which means Dennis has free time which he wants to spend with George. George convinces Henry to not play golf, hoping it means Henry will spend time with Dennis.

The town holds a Paint-up, Clean-up Week campaign, and everyone spruces up their place. Dennis gets into the act with paint from Mr Wilson to paint his red wagon. Dennis paints the wagon and the street corner. Mr Wilson gets blamed.

Both Dennis and Mr. Wilson are ashamed that they have never learned to whistle, and try everything they can think of, including eating very sour cherries, to be able to do so.

Mr Wilson's lodge is raising money by selling raffle tickets to win a car. Dennis buys a ticket because he thinks his mother should get a car.

Dennis is sure that he's going to get a horse for Christmas, even though his parents repeatedly tell him that he isn't (and Mr. Wilson would be sure to object). Then Dennis hears that another boy in the neighborhood has gotten a pony -- and he heads there to claim it, certain that Santa must have delivered it to the wrong house.

Dennis wants more money to buy things he wants, so he asks for his father for an allowance. His father agrees, as long as he works for his money. Giving Dennis money without his help seems cheaper in the long run.

Mr Wilson comes up with another plan to keep Dennis in his own house and away from Mr Wilson. He shows Dennis how to collect money, but Dennis only bothers everyone for pennies and causes Mr Wilson to get arrested.

Dennis convinces Mr Wilson to run for park commissioner.

After hearing talk that Miss Cathcart could use a "best friend", Dennis adopts a lost dog from the pound for her. But when the dog's gentlemanly owner shows up at her door to claim the dog, Miss Cathcart thinks he is the "best friend" Dennis told her to expect.

To prove to Mrs. Elkins that he doesn't hate children, Mr. Wilson goes to great lengths to be kind to Dennis --and hopefully, he will be chosen as the subject of Dennis's publicly-read essay, "My Best Friend".

Tommy does not want his saxophone anymore, so Dennis decides he wants to buy it. Mr Wilson finds out when Dennis asks his father for the money, and tries to talk Henry out of buying it.

While their house is being fumigated, the Wilsons sleep over at the Mitchells'. When Dennis learns that Mr. Wilson has been known to walk in his sleep, he invites all his friends over to see it.

Dennis wants Mr. Wilson to perform as a magician at Dennis's birthday party. Mr. Wilson is reluctant to do so - until he learns that actress Spring Byington will also be guest at the party.

Mr. Wilson is eager for Dennis to go to summer camp. And when Henry is unexpectedly unable to take Dennis and several of Dennis's friends to visit the camp, Mr. Wilson is happy to step in, and takes them there up himself.

Mr Wilson has his car trunk open to use the car jack to change a flat tire. While no one is looking, a Mrs Cathcart's cat jumps in and then Dennis closes the trunk.

Alice plans a visit to her parent's home for a few days. Dennis buys her a gift for her trip and hides it in Mr Wilson's home. Mrs Wilson finds the gift and thinks it is for her.

Dennis wants to get his father a fishing rod for a gift. When he counts the money in a piggy bank, it is not nearly enough. Dennis finds a $50 Confederate bill in the papers from his grandmother and tries to use that.

Dennis sees a mynah bird he wants in a store. The store owner stays he can have the bird free if he buys the bird cage. Dennis talks to his father, and he promises to be good and study for school if his dad gets him a bird cage as an award.

Alice is still visiting with her parents. Dennis' teacher asks students to take home the school pets over the weekend while the heat is off at school. Dennis brings home chicken eggs, but then the electricity goes off in the Mitchell home.

Mr Wilson decides to teach his dog Fremont a few commands. Dennis asks if he can help train Fremont, and Mr Wilson allows him to do all the training. After the dog is trained, Fremont only responds to Dennis and not to Mr Wilson.

Dennis feeds crows in the backyard, causing noise while Mr Wilson is on the phone trying to argue for keeping an old tree from being chopped down. One of the crows grabs a hundred dollar bill from Mr Wilson's and flies off to the old tree.

Mr. Wilson's attempts to build a backyard barbecue are stymied by his teenage helper's playing loud music and by a search for Dennis's wandering pet turtle.

A neighbor kid is building a car for a soapbox race, so Dennis and Tommy decide to build one also. Several people help, and before the race, Mr Wilson makes a last second change. Dennis removes the starter bar and Mr Wilson wins the race.

A fellow-garden-club member asks George to take a picture of a special delicate plant that only blooms at night. George is ready with his camera, but falls asleep before the flower blooms. Dennis asks Mr Wilson to be the Scout Den Mother.

Mr Wilson has been trying to improve the growth of a plant in his garden without success. Dennis accidentally steps on the plant and does not tell Mr Wilson. Dennis replaces the plant with the same plant, but a larger one.

Dennis and Tommy have started their own newspaper, "The Mr. Wilson News", in which they write about Mr. Wilson's daily activities. But when they overhear him playfully telling Mrs. Wilson that he'd give $20 for a raccoon coat like the one he had in college, the boys tell Mr. Krinke, who in turn prints this information in the local newspaper. In no time, the Wilson household is overflowing with raccoon coats from sellers from all over town.

After helping Dennis research a school report about an island off the coast of Mexico --"the Isle of Happiness"-- Mr. Wilson decides he and his wife should spend a year there. But they quickly change their minds when they see how the schoolteacher who will rent their home while they're away plans to change the house; and then learn that their niece, Georgianna, is going to have a baby.

The Mitchell's and Wilson's have dinner together to celebrate George's good fortune in a sale of a stamp collection. The each open a fortune cookie, and George's seems to indicate a bad day. Dennis is determined to protect him from harm.

Mr. Wilson, Dennis and his father try to prove they can survive three days in the wilderness, armed only with a knife, an ax, and a fishing rod - plus a tempting large basket of food, which is only supposed to be for Dennis.

After celebrating Father's Day with his father, Dennis decides Mr Wilson needs his own Father's Day. Dennis manages to do everything to have George enjoy his day. Luckily, one of Dennis' gifts helps George win a lawsuit.

Henry finds a large envelope in the gutter outside his house and is surprised to find it is full of money. Henry asks George to go with him to the police to turn it in. The money is counterfeit. The families go on a picnic together.