On a visit to Hawaii, Robbie falls in love, Ernie almost gets arrested and Uncle Charley is pursued by an old girl friend from 1945, who weighs 200 pounds now. Charley thus finds it necessary to stay in hiding until the plane leaves for home.
Uncle Charley's old seafaring buddy arrives with a wonderful proposition: He wants Charley to join him as first mate for a six month fishing cruise in the Carribean. The family then conspires to demonstrate to Charley that he is not needed, but they really don't want him to leave.
Robbie leaves school after contemplating a very important offer from a former school drop out who now heads his own Real Estate company. When giving some new home buyers a tour of one of the company's display homes, he discovers that the houses are not what they seem.
A genial bum Ernie brings home for dinner outrages Uncle Charley by eating everything in sight and then decides to stay the night even though he wasn't invited. Steve feels that they should let Ernie work things out for himself.
The older members of the Douglas family find their social lives complicated when little Ernie decides to accompany them on all of their dates. Uncle Charley decides he must be the one to put his foot down and set the boy straight.
Other fathers help their sons in a school science fair, but Steve tells Ernie he's on his own. Soon his project turns to disaster when his very crudely built electric clock absolutely refuses to run. After vainly pleading that most of his classmates are getting parental help, on the day of the fair, Ernie must be forced to go to school.
Ernie Douglas's new school friend is little Laszlo, whose gypsy family is camped outside of town. Soon the gypsies are camped on the front lawn of the Douglas home. To Steve's amazement and Uncle Charley's disgust they stage several hours of singing and dancing.
Uncle Charley's romantic tales of adventure captivates Ernie's teacher. The pretty, middle-aged lady is fascinated by the old boy's partially-true tales of his exciting life on the high seas. Soon the ex-seacook is aghast to learn she has given up her teaching job and he is further torn when she explains her savings will buy them both a one-way ticket to Pango-Pango and asks him to marry her before they leave.
To help out his Dad, Steve, Chip pretends to like the aggressive as she is pretty, daughter of a new executive woman that his dad is dating. Chip has the romantic notion that his close relationship with the daughter might help the social plans of his father.
Chip Douglas's junior high school is having an Olden Days dance and the boys are to bring their mothers, and the girls their fathers. Chip finds trouble going steady with two girls at the same time and arranges for Steve to escort his classmate's widowed mother.
Robbie is crushed when he learns that Denise DuBois, a French exchange student that Robbie had hoped to marry, has accepted his friend Tom's proposal of marriage the night before.
Robbie Douglas tries to impress his girlfriend by competing with a handsome bullfighter against a killer bull, but has to flee for his life when the bull charges him.
Uncle Charley puts down a deposit on a vacation lot at beautiful Whispering Pines, only to learn he's been hoodwinked in a high pressure real-estate operation. The family discover that it is located at the bottom of a steep canyon. It is next to a tumbledown shack, occupied by a slovenly family who prove themselves completely undesirable as prospective neighbours.
Ernie's friends all boast of their dads' college athletic trophies, which forces Steve into a grueling two mile cross-country race with the other fathers. Two of the men, once athletes are eager for the contest, but Steve thinks it is silly.
Television viewing at the Douglas household has dropped to zero because Uncle Charley, annoyed with the boys' quarreling about choice of channels, has withdrawn all TV privileges for a week. Robbie, a member of a new program committee, eagerly joins his co-ed girlfriend in her plan to bring true drama to the people. However, after viewing the show, the family isn't sure their attempt at 'realism' is really real.
Steve Douglas passes up his company's offer of a weekend in Rio because Saturday is the start of trout season. The boys do their best to get Steve to make Ernie his fishing buddy so Robbie and Chip can get out of the annual trip.
Robbie is delighted when college classmate Peggy moves in next door, and the pair immediately go to work on a joint assignment for their Shakespeare class. He plays Romeo to her Juliet when a feud between the two families seems imminent.
Ernie's excited reports of seeing a flying saucer are received with skepticism, but the next day he not only sees the weird vehicle again, but he snaps some pictures and is later told by the Air Force to keep quiet about it.
Chip's romance with a classmate flourishes when he rents a horse and buggy so as to impress the girl's strict, old fashioned grandmother. She is impressed, but still insists that the kids stay at home to have a taffy-pulling marathon.
Ernie sneezes as he brushes past the family dog, Tramp, and when a doctor verifies the boy's allergy to dog hair and says the dog must go, Ernie packs his bags as he feels Tramp has seniority over him in the family.
Steve Douglas meets a celebrated popular vocalist of 20 years ago whose career seems over. Although her famous voice is still there, the public demands music in the current style. Steve helps her update her style when he arranges for her to sing with Robbie's combo, the Greefs.
When Ernie sends for a picture of Chip's favourite movie star, planning to give it to him as a birthday gift, Chip gets an actual date with the movie starlet for a publicity stunt and is astounded by all the resulting hoopla.
Robbie is immediately infatuated when he hires a pretty chemistry instructor as a tutor, and their friendship seems to be blossoming. But when he finds out that his father has been dating her, the shock affects his ability to concentrate on his studies.
When Robbie's girlfriend's father calls from out of town and asks him to deliver a birthday cake to her, he thinks there might be a fortune in performing this birthday service and immediately goes into the cake business.
Ernie feels left out when the Douglas family orchestra begins to practise. Uncle Charley tries to teach Ernie the violin but runs into a major obstacle -- the boy's lack of obvious talent.
Robbie films a 'way out' movie for his Cinema class with the aid of a non-talented, 'way out' co-ed who earnestly tries to make an 'honest' motion picture. They begin a long week of filming uncinematic gems spotlighting the Douglases dull, drab meaningless family routine.
Steve Douglas gets a parking ticket from Robbie's girlfriend, a pretty meter maid, and another citation for not having his driver's license renewed -- and then flunks his driving test. Soon Robbie realizes that he's given his father last year's manual to study and that some laws have been changed.
Because Robbie's friend wants him to understand Italians better, he invites Robbie to his home. Robbie runs afoul of an old custom when he takes a girl walking in the park and learns that he is expected to marry her.
Three fathers face their sons in a quiz game at a school entertainment night, and when the boys easily beat the dads so much interest is aroused in town that a re-match is scheduled on the local television station.
Steve Douglas receives a perfumed letter from an old girlfriend announcing she will stop by and see him. She terrifies Steve by acting as though she plans to accept a proposal of marriage he hasn't made. Steve does his best to convince her that his old college chum is the man for her.
Steve Douglas takes his family to his birthplace of Bedford Springs. He tries to locate his 1940 fiancee Ellen, married and still living in town, but he is disenchanted by the changes in her. Still pretty, she lives with her obnoxious husband and ill-mannered children.
The usually all-male Douglas household becomes a refuge for an attractive girl dancer who has been evicted from her apartment, when Steve attends an office stag dinner. He takes her home where he lends her some of Robbie's clothes.
