A notícia de que a mãe está grávida deixa os três filhos Keaton atordoados e em pânico, embora a mãe lhes tente mostrar o lado positivo da situação.

Mallory anda muito entusiasmada com o seu trabalho numa boutique e isso provoca uma descida das notas na escola. Os pais, Steven e Elyse , acham que ela deve deixar o emprego, mas Alex aparece em defesa da irmã , com uma proposta que poderá ser a solução para o problema. É que, para Alex é muito conveniente manter a irmã fora de casa e , assim, ele arranja uma forma de ela se manter no emprego e ao mesmo tempo manter as notas na escola.

Steven e Elyse estão a planear fazer um fim-de-semana com os filhos antes do nascimento do bebé. No entanto, ficam muito desiludidos ao verificarem que os miúdos não estão interessados e preferem ir sair com os amigos. Assim, tanto Elyse como Steven ficam muito desapontados quando Mallory e Jennifer, por um lado, se mostram aborrecidas de morte e Alex vai sair com uma namorada, fazendo com que os planos de Steven caiam por terra.

Alex está encantado com o facto de ir ter aulas na faculdade com o Professor Ephraim Bronski, um dos seus ídolos. No entanto, Alex está tão empenhado em impressionar o Professor, que se espalha logo na primeira aula e é humilhado por Bronski em frente de todos.

Doug, o melhor amigo de Alex, apaixona-se por Eleanor e casa-se. Alex não aceita o facto de que alguém se tenha intrometido na sua amizade com Doug e não vai ao casamento. O problema reside em que Alex se recusa a aceitar que ele e os amigos cresceram e tenta por tudo agarrar-se ao passado.

Alex is teamed with long-time rival James Jarrett and assigned to work at a ""hotline"" crisis center to fulfill a course requirement, and the two end up in a crisis of their own when they get a call from a suicidal student.

As an economics student, Alex finds it demeaning to be forced into a public service position, but his experiences at the crisis center gives him a new outlook on life.

While Steven and Elyse are away on vacation, the Keaton house becomes a hotel for the weekend after Mallory accidentally crashes her parents' car into a telephone pole and the kids need to raise money for auto repairs.

A lot of people are in town for the Leland homecoming game, so Alex decides to take advantage of the situation and rent out rooms but suddenly he's swamped with renters and the house looks like a three-ring circus.

When his best friend, Doug, meets and falls in love with Eleanor, and decides to marry her, Alex resents the fact that someone has come between their friendship and refuses to be in the wedding.

Alex cannot accept the fact that he and everyone around him are growing up, and desperately clings to his old ways.

Steven and Elyse plan a nostalgic weekend with the kids before the baby arrives, and are crushed to discover that the children are not at all interested in reminiscing about old times, they'd rather be with their friends.

Elyse's camping trip with Mallory and Jennifer is cut short when she realizes that the girls are bored to death, while Steven's plans to spend time with Alex at home are crushed when his son leaves on a date.

Alex plays Cupid to help his shy pal Skippy get together with Jane, the girl of his dreams, but his good intentions goes awry when the girl falls for him instead.

When Skippy and Mallory find Alex locked in a passionate embrace with Jane, Skippy accuses him of stealing his girl.

Because of Elyse's pregnancy, the family decides to get a housekeeper, so Alex hires the lovely Karen Nicholson, a totally incompetent young lady whom the family immediately adores but Steven insists she must be fired.

Despite the fact that Karen has no domestic skills and is rapidly destroying every appliance in the house, the kids love her and Steven has a difficult time trying to fire her.

Alex's chances or acceptance into a smug college fraternity are dependent upon his having a knockout date for the pledge dance and when the girl cancels he pleads with Karen, the housekeeper, to accompany him but his problems are far from resolved when they arrive at the dance.

Karen reluctantly agrees to be Alex's date, but does not tell him why she is so hesitant to go.

Alex becomes involved with Donna, a young, unwed expectant mother from Elyse's natural-childbirth class but his interest in her becomes an obsession when he starts planning for her child's future and acting as if they were a real family.

Donna is flattered by Alex's concern for her and her unborn baby, but soon begins to realize that he is becoming a little bit too helpful.

Mallory is crushed when her favorite aunt dies suddenly, but her feelings of sadness turns to anger when family and friends at the funeral seem to be taking Aunt Trudy's death too lightly.

Mallory feels that she has lost her best friend, and is shocked that no one else seems to share her grief.

The Keaton family is transported back in time when Alex dreams he is at the Constitutional Convention at 1776, but history is off track. Steven Keaton is Thomas Jefferson and has just turned down John Adams' request to write the Declaration of Independence, so it's up to Alex to convince him to do it.

Alex falls asleep while working on a college term paper on Thomas Jefferson and dreams that his family and friends are living 200 years ago.

To help Steven during pledge week at his TV station, the Keatons reluctantly agree to be a part of the entertainment, but the audience gets an unexpected show when Elyse goes into labor right on camera while in the middle of a song.

Elyse realizes that the baby is on the way. she and the kids begin to panic when they realize that Steven had to rush home to fix a plumbing problem and is now trapped there by a snowstorm. His TV set shows him what's happening at the station.

Still trapped at the television station, Elyse realizes she cannot make it thru the snowstorm to the hospital and prepares to gibe birth in Steven's office. Meanwhile, stuck at home by the same storm, Steven enlists the help of Bud the plumber and his truck, and heads for the hospital, thinking Elyse will be there.

Elyse makes a plea on camera to Steven, wherever he is, to come to the station, so Steven, the doctor, the plumber and Skippy all frantically head for WKS, hoping they arrive in time for the birth.

The Keaton family adjusts to life with the new baby but while everyone caters to the new arrival, Jennifer struggles with jealous feelings about not being the baby of the family anymore.

When Steven and Elyse realize that Jennifer feels left out, they overcompensate by trying too hard to make her feel loved.

Alex and his good friend James go into business together as tutors for their fellow students at Leland. However, their competitiveness threatens to undermine their business let alone their friendship particularly when one of their students turns out to be a very attractive young lady.

With two careers, three bickering children and one demanding baby, Steven and Elyse can't seem to find any time for each other. But when they do finally take the time for a quiet evening alone, they miss all the chaos.

With the rest of the family away for the weekend, Mallory is excited about having the house to herself until she is accidentally locked in the basement with the person she'd least like to be with her adoring neighbor, Skippy.

The mismatched pair do, however, come up with a unique way to keep warm and share some tender moments while waiting for their rescue.

Steven takes a nostalgic trip to his hometown following the death of his father and, with the support of Elyse and the children, tries to prepare his mother for her new life in a special two-part episode.

Good and bad memories of Steven's childhood (including flashbacks to his boyhood) are stirred up as he sorts thru family photos and heirlooms. But an on-going rivalry with his older brother Robert, and the unsettled feelings he has about his dad make it a difficult period of adjustment for everyone.

Steven takes a nostalgic trip to his hometown following the death of his father and, with the support of Elyse and the children, tries to prepare his mother for her new life in a special two-part episode.

Good and bad memories of Steven's childhood (including flashbacks to his boyhood) are stirred up as he sorts thru family photos and heirlooms. But an on-going rivalry with his older brother Robert, and the unsettled feelings he has about his dad make it a difficult period of adjustment for everyone.