Steve is going on a business trip to Japan and thinks he might as well take his family along with him. Mike gets involved in a new romance with another beautiful girl named Kimiko and suddenly he forgets his girlfriend back home.
Robbie and Hank think there is only one thing in the whole world that impresses girls -- money! So they decide to open their own home help unit in the hope of making the big bucks that they are constantly in need of. However, they run into competition from Chip who organises baby-sitting as a means of increasing his allowance to buy a new bicycle.
Tramp supposedly takes a nip out of pampered young Alan Edgerton and the court case that follows, gives Robbie the chance to help out the family's lawyer with some special investigating when he realises he can prove that the dog acted in self defense.
College freshman Mike Douglas has invited the reigning campus beauty to his fraternity's Saturday night dance, but he sort of doubts that she'll accept. So to cover all bets, he invites another girl too, which lands him in more trouble than he bargained for.
Homeward bound from a long business trip Steve meets an old friend on the plane and he suggests that her daughter stay at the Douglas household while her mother gives a lecture in town, but unfortunately everyone else at the house has plans and Steve is left to entertain the girl.
Chip and his friend Sudsy see a Halloween spook carrying a candle in the neighbor's vacant house next door while out trick or treating, and are frightened out of their minds, but Steve and Bub will not believe them.
Robbie get in trouble with the big brothers of a girl he likes when he takes her picture.
A cooking contest at school upsets Chip when he realizes he doesn't have a mother to submit a recipe. But there is much rejoicing when Steve's favourite recipe reaches the finals. The prospect of winning keeps Steve on edge, much to the displeasure of the boys and Bub.
Chip is thrown out of the neighbourhood clubhouse because he cannot convince the older boys that he is all grown up. He makes a bargain -- he will fight one of the older boys for the privelege of becoming club mascot. But he doesn't count on being sent to hospital to have his tonsils removed the very day of the big fight.
Robbie goes on a date when he was suppose to write a term paper. Mike gives him a paper that Steve wrote and received an 'A'. Robbie copies it but gets an 'F'. When Steve talks to the teacher he finds out that the paper is plagiarized. Embarrassed Steve must explain to Robbie why he got the 'F'.
A summer heat wave has tempers flaring. Steve remains cool and calm until some important plans go missing and he thinks it might be in the pile of papers given to the boy scouts for its paper drive.
Mike is dragooned into acting as the sole judge of a campus beauty contest and discovers that the hazards of choosing a winner to be a formidable task. Especially when he realizes his girlfriend is a contestant.
Steve is in too big a hurry to get home to his family and spread the good news of his upcoming business trip to Bolivia, but hurts his back by throwing out his sacroiliac and is convinced that there is only one doctor who can help him.
Robbie wants to date a cute fifteen year old blonde, whose mother campaigns for Steve's co-operation to end the relationship, but this move almost ends in another romance. Robbie starts shaving and Steve realises Robbie is becoming a man.
Chip and Sudsy see a model auto at the toy store. When he is reminded that he is doesn't have a mother to nix the idea, he tries to persuade his father to buy it. But they both don't figure that Bub will have his say on the subject.
Chip gets a relief from boredom when Steve's friend invites him to a birthday celebration for his ""honorable"" grandfather, and Robbie finds it hard to keep up with a new girl at school who seems unimpressed with him.
Mike has the job of recruiting some campus models for a fashion show and when a gorgeous store representative stops by to give him help, he forgets there are any other girls in the world. With Robbie's help, he tries hard to capture her affections with displays of serenading on the guitar.
Steve's reluctance to make a business trip to Rome with the family puzzles everyone in the Douglas household except Bub. He remembers that Steve and his late wife were once there and that the place may hold too many memories for him.
Steve encounters a sweet, old-fashioned 16-year-old at the bus depot, who reminds him of someone from his high school days. After hearing about his family, the girl wants to go on a date with Robbie, who finds she is more wordly than his father had told him.
When he is badgered by one of his co-workers to join the company musical combo as a saxophonist, Steve, who is rather apprehensive about the situation, dreams of being chased by a man carrying a trumpet -- a man who looks very much like his workpal.
Chip is overcome with loneliness when Sudsy starts spending all of his time with a new boy in the neighborhood. The entire household rallies together and their efforts to compensate the youngster succeed almost too well.
The members of Robbie's high school wrestling team need higher grades to remain eligible, so they choose Steve as their tutor. Soon the house is quarantined for Diptheria, and when Bub doesn't get his long-awaited rendezvous with ""Old Roy,"" the biggest catch in the lake, watch out boys.
Bub, representing the older generation, makes some suggestions for Robbie's school club carnival, but to the Committee they sound a mite old fashioned. The junior crowd scorns at the ideas until they see them in action.
Robbie's science master announces a special achievement award for being a straight 'A' student and to his embarassment, Robbie wins it. This causes more trouble than he could have imagined but Steve does his best to assure Robbie that he did deserve the award.
When Robbie and his friend complain about being broke, another student offers them a pig to fatten in a profit-sharing plan. When the time comes for it to be slaughtered however, nobody is quite sure that they want to do it.
With his Air Force Reserve crew depending on him for an engine maintenance exercise, Mike is faced with having to abandon a date, as well as a baseball match, all of which is just part of his same crowded weekend.
Bub, an inveterate contest buff, finally hits the jackpot, winning a prize worth $1,000 in a TV competition. But when the boys learn that a British butler will be part of the family for two weeks, they succeed in shaking the impeccable and usually unflappable gentleman.
While Steve and Bub are away, Chip, Robbie and Mike face the problem of caring for two sick foundlings, a wild bird and a frightened girl, who they learn is a runaway from a maid's job in Philadelphia where she has been unhappy.
Steve lays down the law to Chip, warning him he'll be grounded for a month the next time he loses or misuses someone else's property. Meanwhile a woman who is rounding up second hand items for a rummage sale visits Bub, who offers an old Tiger skin rug.
Mike learns the importance of indirect questioning in his psychology course when Robbie is sought after by eight classmates. Mike sets out to determine by voluntary questionnaire and graph who would be the most suitable scientific choice.
Robbie's economics teacher gives each student a fictional $10,000 dollars to invest in stocks but Steve's boss at work gets the impression that he has some really hot tips.
Bub condemns modern-day youth as he reminds his three charges how different things were when he was their age. The boys try to convince him that they aren't as lazy as he thinks they are.
Chip spots a runaway toddler and disobeys orders to stay home and wait for someone who is coming to pick up some plans.
Chip reads a news item about someone winning a date with an actress and gets the idea of raffling off a date with a big star - his grandfather Bub.
After a series of disastrous blind dates, Robbie and Hank set up a romantic employment agency that works to avoiding dull dates by matching couples with likewise interests.
To help Robbie gain himself of the attentions of a beautiful girl, Bub is willing to give up two tickets to a pre-sold sellout fight. However part of the bargain entails that he take the girl's disagreeable Aunt to the movies.
The family is so engrossed in searching for a missing, valuable stamp that they ignore Chip's announcement that he is getting rich everyday.