Webster goes to the race track and learns that one of the horses will be put down because it's too old to race anymore. Webster tries to save the horse.
Katherine's jealousy over George's successful Love in the Afternoon talk show—which he co-hosts with a sexy woman—makes Webster worry divorce may be in their future.
Webster writes stories about other teacher's love lives in the school paper. The information then puts Katherine's teaching job at risk because Webster got the information by overhearing her gossiping about them.
George and Katherine have different ideas on how to celebrate Webster's birthday. George wants to take him to a professional wrestling match and Katherine wants to take him to an opera.
Webster discovers that a woman who is said to be a witch is not a real broom-riding witch, but a woman who is lonely and needs someone to care for her.
The family learns that Papa Papadapolis is illiterate, and he is greatly ashamed of it. To try and ease the tension, George and Katherine enroll him into a class, after some manipulation and persuasion.
George is so obsessed with Webster winning a derby, that he builds the car without him, hurting his feelings since he wanted them to build the car together.
Webster starts buying his lunch and the school bully keeps taking Webster's money. After George and Katherine get word about it, they try to stop him and the two end up being friends.
Webster asks permission to buy a BB gun and he resorts to responsibility to get one. After getting one, and practicing with his friends, he accidentally kills a bird. This bird has babies and he takes the responsibility of raising them on his own.
Jerry dresses up like a clown and takes Webster to the leukemia ward at the children's hospital, where he makes a new friend and realizes how lucky he is to be healthy.
Webster makes Katherine a dress for her birthday. She says that she likes it, but avoids wearing it when she is asked to put it on when they go out. She then tells Webster how she really feels about her gift.
Webster gets a chain letter. George throws it away and things mysteriously go wrong. Webster does bad on his test, there is a spider, and Papa Papadapolis falls down the stairs.
After cheating on Phil, the producer gives Phil's part to his now ex-girlfriend, which leaves Phil fired. Meanwhile, at George and Katherine's 2nd honeymoon the power and heat go off.
Webster goes to Hollywood with Uncle Phil and his girlfriend. Matters turn worse after Uncle Phil's girlfriend cheats with Phil's producer. Meanwhile, Katherine gets sick while she and George are on their 2nd honeymoon.
Webster's friend Rob picks up a tabloid and asks Webster some questions from it. Webster gets the questions right and according to the tabloid, Webster is an alien from Jupiter and he starts to believe it.
George wants to live on the ranch, Webster wants to save Moonhunter and set him free, but after all the excitement, they decide to head back to Chicago.
The Papadapolises visit Lizard Flatz, Arizona and encounter Dusty, a man with interesting stories, a ranch, and Moonhunter, a horse that seems to be a legend, but ends up a reality after saving Webster from a rattlesnake. Moonhunter gets caught by some greedy no-gooders, and Webster almost gets killed.