After Dave's boss, Mr. Kelley, asks him to do several menial tasks, Dave feels like he's not getting anywhere in the law profession, so he considers quitting his job and entering the advertising field.
Rick's girlfriend is secretly knitting him a sweater. When she turns down several dates to work on the project he begins to date another girl, who also knits him a sweater. Now Rick has two sweaters and two girlfriends to juggle.
David and Rick's fraternity tries to find an affordable piano to use for their upcoming Christmas party. The brothers are just about to give up when they meet the Stewarts who offer them their old, but serviceable, upright piano. The boys find a sheaf of Christmas carols in the piano stool and convince their fraternity brothers to invite all their parents to the party - and the Stewarts, too - for an evening of Christmas carols, dance and punch.
Rick is in charge of the committee counting the votes to elect a new Prom Queen. His girlfriend is among the candidates, and Rick does his best to keep the winner's identity a secret from her and everyone else until the prom.
A reporter for the college newspaper always seems to know all about the activities of Dave and Rick's fraternity. The fraternity brothers are convinced that Rick is supplying her with inside information.
Ozzie takes a message from David's new job at the law office concerning some important documents of his boss, Mr. Kelley. But David is not to be found so Harriet and Ozzie track the attorney to a ski lodge to deliver the papers.
The Nelson's friend, little boy Barry, is expecting a new arrival to his family, and he hopes it's going to be a baby brother. He spends a few nights at the Nelson's, while his mother goes to the hospital "to pick up the baby".
The sorority girls issue a proclamation dictating a dress code that must be adhered to by fraternity boys, when going out on dates. The fraternity boys fight back, and the war of the sexes escalates from there.
Harriet asks Ozzie to check for gift ribbon in the hall closet. When a box of wrapping paper falls on the floor, a small unmarked Christmas present is found and the Nelson family tries to figure out who it is from.