Multi-millionaire Phillip Drummond, who has agreed to the death-bed wish of his housekeeper to raise her two sons as his own, welcomes Arnold and Willis into his lavish penthouse.

Arnold's eavesdropping leads to trouble when a misunderstanding causes Willis and him to think that Mr. Drummond no longer wants them around.

Mr. Drummond's mother arrives and finds there's a lot she doesn't like about her son's new sons, but she soon learns a valuable lesson about what's really important in a person.

Arnold ignores warnings and continues to drop water balloons from the balcony. Mr. Drummond's decision to punish Arnold for the prank becomes a learning experience for Willis too.

When Mr. Drummond tries to get Arnold and Willis into an exclusive prep school, it turns out to be just a little too exclusive for everyone's tastes.

When Arnold loses his favorite doll, he makes sure that his misery is shared equally by the various members of his household, who soon try everything to get it back.

When Arnold is in trouble for putting his gold fish in Mr. Drummond's hot tub, Willis insists that it is wrong to convict him without a trial.

Willis puts Arnold in training to fight the local bully, but Mr. Drummond insists more civilized solutions be employed.

Willis invites his neighborhood club from Harlem to visit, but things get out of hand when he tries to impress them with his new wealth.

Mr. Drummond's intention to marry an attractive widow doesn't meet with his children's approval, and they devise a scheme to turn his "romantic" proposal into a disaster.

A lonely Arnold comes up with a method of gaining his family's attention. Unfortunately his plan works too well; he ends up with everyone's attention, including the family doctor.

LaWanda Page guest stars as a cousin of Willis and Arnold who, after seeing the boys in their comfortable new surroundings, knows she should stay closer to her long-lost relatives.

Drummond hires a tutor for Willis and Arnold who does practically everything but teach.

The kids devise a scheme hoping to make Arnold convince the new landlord to let the family keep the penthouse.

To get rid of his pesty little brother, Willis divides the bedroom in half and spends more time at his friend's house.

Mr. Drummond and family gather around their Christmas tree and recall the many humorous incidents that the family has shared since Arnold and Willis moved in.

Mr. Drummond and family gather around their Christmas tree and recall the many humorous incidents that the family has shared since Arnold and Willis moved in.

When Mrs. Garrett decides her life as a housekeeper is unfulfilling, she ends up being a guest in the Drummond home, and then makes an important decision concerning the future.

In order to earn the money to buy disco skates, and to prove a point to Mr. Drummond, Willis gets a job... but is fired on his first working day.

When Arnold is witness to a hold up, the robber tries to ensure that the youngster will not identify him.