Frank and Sandy are going to be very busy for the next two days so Dave is put in charge. He takes the job very seriously. Mark has a confrontation with the new school bully and has to avoid being beaten up.
An old friend of Michael's suddenly turns up just as Michael is about to go away on a camping trip. The friend is to attend a reunion of his flight school. He needs a date and Dave volunteers Sandy, and she forces Dave to go as well.
Sandy trips over at a baby shower, falls down some stairs and hits her head. This causes her to completely lose her short term memory. Her inability to remember events causes some awkward situations, especially for Dave.
Mark is in love with a new girl in his class but she is infatuated with Willie. Willie uses Mark to impress her. Dave is to perform in a charity concert but needs an act. He tries ventriloquism and then magic, both unsuccessfully.
Mrs. Poole is on edge as her mother-in-law is coming to stay for a few days and she gets on everybody's nerves. Dave is eager to buy a new car and sells his old car to Mark and Willie. Unfortunately, it is a lemon.
Dave is dismayed because Annie is going home for a visit. Mark is promoted to acting manager at Bossy Burger. When the other workers take advantage of him, he goes overboard. Michael tries to fix a power outlet, but the job gets bigger.
There is a new neighbour who is a bit mysterious and Dave suspects that he is a criminal. Willie employs Mark to tutor him in biology when Michael is furious about his poor results. When he succeeds the teacher accuses him of cheating.
Sandy's request for funding for a literacy program is denied so she decides to quit. She writes the letter of resignation but doesn't send it. By the next morning she has had second thoughts, but Dave has already sent the letter.
Sandy organises a caterer for the school prom coming up. However, Dave intervenes and causes the caterer to walk away from the job. Willie asks a reluctant Brenda to the prom, which leads to them breaking up after an argument.
The Hogans are off to California to help cheer up Sandy and Michael's father, who has just gone through a divorce. Whilst there, Mark and Willie become interested in the local girls, and David crashes a film set.
After the storm, Sandy tries to convince Lloyd to return to live with them in Chicago. Mark gets it into his head that Cara is being unfaithful so he goes on a date with another girl. Dave finally gets fed up with Jennifer's demands .
To help out Mrs. Poole for a short time, Sandy looks after her niece, who is baby girl. However, as she has to leave, Sandy passes the baby onto Dave to look after. Dave then tricks Mark and Willie into looking after her.
Mark challenges Willie to try out for the lead in the school play and, to everybody's surprise, he gets the role. Dave talks Sandy into stop buying so many raffle tickets. Lloyd and Michael start to play golf together.
Dave's 21st is coming up so Michael gives him a watch that is a Hogan family heirloom and which is given to the eldest male in the family. Unfortunately, he breaks it. A mix up leads to Mark and Willie being sacked from Bossy Burger.
Sandy's ex husband is getting remarried and he asks Dave to be his best man. Sandy is not happy with the situation but goes to the wedding anyway. Lloyd buys Mark and Willie a motorcycle without asking Michael first.
Dave is having a woman drought so he decides to wear Michael's pilot's uniform. He also uses Michael's name and goes to a bar with Burt with some initial success. Things go wrong when the woman he meets turns up at the Hogan house.
There's conflict in the video store between Lloyd and Michael. Dave helps Burt run for student body treasurer. Mark and Cara are forced up to his room to study for a test when they fall asleep. Nobody believes nothing happened.