The family visits the Tumbleweed Ranch in Lizard Flats, Arizona, where George once went as a child. While George is disappointed at the modernization, he is happy to see that Dusty, the old cowboy who was there in the old days, is still around. After Webster hears Dusty's campfire retelling of an Indian legend about a white horse named Moonhunter, he sees a white horse that he thinks is the same one from the legend. Webster wants to catch it, offering the wranglers co-ownership in return. However, Jack, the head wrangler, has other plans.
Webster's class has to do a report on what it's like to be married and raise a child; he has been assigned an arrogant girl named Annette as his "wife," while their "baby" is an egg named Chester who meets with a tragic fate at the breakfast table.
Webster has been getting home late and not calling; George decides to ground him, but Katherine, who is now majoring in psychology, comes up with a more novel idea: that Webster act as the parent to her and George to see what it's like from their perspective.
When Katherine's mother dies of a sudden stroke, she becomes withdrawn from the world. She won't go to her classes or go out with friends or family, and she refuses to go to Webster's party even though she promised him that she would.
Webster has a dream to make a free throw from a regulation basketball court, like his favorite basketball player, Patrick Ewing of the New York Knicks. When George takes Webster and Katherine to New York, Katherine's former sorority sister gets mid-court tickets to the Knicks-Celtics game for Webster and George as well as opera tickets for the two of them. Unfortunately, things do not go as planned.
Webster travels to Hollywood to see Uncle Philip, who has been signed to do a movie musical called "Rockin' Feet." He also has a surprise for Webster: he's dating a woman named Sherette. When they visit the Paramount lot, Webster sees Sherette make her move toward the film's producer.
While at first Philip doesn't believe Webster when he tells the truth about Sherette, he eventually figures it out when his part in "Rockin' Feet" is rewritten for a woman - and that woman is her. Back in Chicago, Katherine and George's attempt at a second honeymoon is spoiled when a blizzard knocks out the power and the heat.
Webster is upset when his friends tease him about having a babysitter, so he persuades Katherine to let him stay home alone for an hour. When he gloats about this to his friends, two older boys who hear this take the opportunity to rob his house. Meanwhile, Bill hires his nephew Skippy to represent him in a lawsuit over a car accident.
When Webster throws out a chain letter that promised bad luck if he doesn't send it to 25 people, bad things start to happen. He gets a D in math, Katherine's beaded bracelet breaks, and Papa is hospitalized because of what he says is "bad luck." This makes Webster think the chain letter was right, but Katherine and George must find a way to convince him that it's just a series of coincidences.
As the Parkers' 25th wedding anniversary approaches, Webster shows Katherine a picture he took of Bill's car at a hotel. She tries to confront Bill with this, but the clumsy way she does this makes Bill think she's interested in him. Bill tells this to Cassie, who refuses to believe it, but when George hears about it and goes to talk to Cassie, Webster, who doesn't understand what they're misunderstanding, tries to explain it to Katherine who draws an equally wrong conclusion.
Katherine gets a homemade dress as a present from Webster: an unflattering lime green one that says "I Love Paris" and has a large, battery-powered, lighted Eiffel Tower embedded on it. She can't admit to Webster that she doesn't like the dress, and he wants her to wear it for a special occasion. Cassie tells her to wear it as she goes out the door and then change at the neighbors' house while Webster isn't looking. The day she chooses to wear the dress is the day she participates in an experiment where she and other students will be observing four children's ...
George is upset that a younger pro football player has been signed to do the morning sports report. Webster suggests that he cover his hockey team's charity game as a human interest story. The station agrees, and George's report goes over so well that he starts to get more children's sports stories, which distresses him. Webster is upset when he overhears him saying so, but his spirits pick up when he and Rob audition for the job of covering kids' sports at the station.
Rob spends the night with Webster after he and his mother have dinner at his house. The next morning, his Dad comes to pick him up in his two-seat convertible. Webster doesn't see anything wrong until George and Katherine explain to him that Rob's parents are divorced and have been fighting over custody; they believe his father may have tried to kidnap him.
Ever since his sister was diagnosed with leukemia 10 years ago, Jerry has volunteered as a hospital clown for children with leukemia, and he invites the family to join him. George refuses to go because he saw too many dying children during his football career and can no longer handle it, but Katherine and Webster go with him. At the hospital, Webster befriends Mark, a boy from Wisconsin who is in remission from leukemia, and invites him to stay the night. At the house, he gets more activity and fun than his overprotective mother allows him to have.
Webster visits "Uncle" Jake Tyler, a collage classmate of George and Travis. Jake is a country music singer who, after his son died and his wife divorced him, has chosen a new career path: taking care of foster children. When one of their mothers comes back to pick him up, he has trouble letting go.
Papa is staying home with Webster while George and Katherine are in the Bahamas. Webster complains that he doesn't get to go with him, but Papa reminds him of all the places that he's been, as seen in past clips.