When Adelaide goes away, Drummond hires a temporary housekeeper to take her place. With the new housekeeper, Arnold soon realizes that she reminds him a lot of his mom and tries to arrange it so that she and Drummond fall in love.
Everyone is planning a huge surprise party for Drummond on his 50th birthday. But the real surprise is a very tragic one: On his way home, Drummond is critically injured in an accident caused by a drunk driver.
When he sees that Arnold is heartbroken after not making his Pee Wee league football team, Drummond secretly meets with the coach and agrees to buy the team new uniforms in exchange for Arnold being given a spot on the team.
When Arnold finds out that he will only grow to be 5 foot tall, he becomes very depressed. To make him feel better, Drummond introduces him to a friend's daughter who is very upbeat despite being confined to a wheelchair.
Arnold's poor dental checkup has Drummond suspecting that the easy availability of junk food from vending machines at school is to blame. But when Drummond begins a campaign to replace the hot dogs, cookies, potato chips and soft drinks with more healthy foods, Arnold's friends try to convince him to get his father to reconsider.
Arnold's joy of being transferred to an all-white school (and riding a bus to get there) is shaken to its very core when a racist busing opponent calls the Drummond household warning the pro-busing family patriarch not to send his black children to the new school, or else.
Tired of looking like a 15 year old, Kimberly turns to Blair for help in looking like an older woman. She meets with immediate success when she accepts a date from a 25-year-old man (who thinks she's at least 20). Arnold and Willis find out about the date and sneak off to the movie theater to try to stop the date before Drummond finds out.
Arnold gets annoyed with the new girl next door and makes it known that he does not want her at his 10th birthday party. However, when Drummond finds out from her parents that she has leukemia, he tries to get Arnold to re-invite her without telling him of her illness.
With a magazine reporter and Ed "Too Tall" Jones coming over to the house, Arnold decides to show off his talents by putting on a magic show. He plays a silly trick on everyone that leaves him out on the balcony ledge, afraid to move.
Drummond creates controversy with his shareholders when he recommends hiring a woman with whom he starts dating to head up a new division in his company. The children, shareholders themselves, are all for it until Kimberly overhears her talking to a mystery man on the phone.
Drummond is initially excited to hear that he is the owner of a two million dollar piece of land in Harlem only to later find out that the ancestor whom he inherited it from was a slave trader. He must now decide whether to donate it to be used as a community center or decline it.
After getting a D in history, Arnold is forced to stay home from a hockey game to study. While at home, he and Drummond meet Milos, a Czech immigrant who is going to night school to try and become a US citizen.
Willis, the star pitcher of his junior high team, is recruited by a coach from a high school with a reputation for producing major league talent. When Drummonds learns that attending this school entails lying and grade fixing, he forbids Willis to go.