The Colonel and Grandma Ruth return from being out of the country for six months. Simon surprises his grandparents with his new haircut. Matt decides to move out of the house and gets his own apartment with John Hamilton. Aunt Julie's new husband Hank gets Matt a job at his hospital working in the cafeteria. Eric begins to suffer a mild heart attack due to the stress from his job.

Eric develops a child-like fascination with life when he takes a much-needed vacation after his heart attack episode, while Annie runs into interference with each of the kids. Meanwhile, Simon assumes the role of the 'man of the house', but feels Matt is undermining his authority when he keeps on making fun of him. Also, Matt grows uncomfortable with the blossoming friendship between his girlfriend Shana and his roommate John Hamilton while he's busy with other issues. Also, Lucy finds a direction in her life with her interest in Habitat for Humanity after taking her fathers advice.

Each of the Camden's are learning a lesson in equality as Annie and Lucy join together to protest the mistreatment of women in Afghanistan. Eric counsels a young couple about the importance of sexual equality in a marriage. Simon considers dropping out of a cooking class he enjoys because he is the only boy enrolled. Also, Mary helps Ruthie with her secret plans to defy convention and play on the school football team. Meanwhile, Shana confronts her long-lost father who abandoned her family 20 years ago.

With Annie and Lucy adding a new bathroom, and the need for a new car, Eric is depending on his built-in annual raise from the church board. However, when the church deacons gets the wrong impression about the Camden's financial situation, they reject his annual raise. It's up to Ruthie to save the day when she realizes what is going on and to convince them to change their minds about their plan. Meanwhile, a young hospital patient (Josh Evans, ""Passions"") offers Matt some career advice. Also, Simon attempts to entertain a classmate who has a crush on him.

Mary and her friend Corey Conway learn that they have been named recipients of their senior classes ""All Sports Award"" and they are both thrilled. Although, the local businessmen revoke the honor from Corey when they learn Corey is a mother. Angered and hurt by their actions, Mary gives her reward to Corey in front of the entire assembly. On the home front, tensions build after Eric and Annie find a bag of marijuana in Simon's new friend's backpack. They confront his family (who at first deny there is an issue), but after a successful intervention with the police, the boy's father agrees to seek counseling and to find a job. Meanwhile, Matt faces a disciplinary action after he breaks the honor code during a school exam. Also, Lucy questions herself whether she should help a boy she likes to access the school's computer system when she's working in the attendance office.

Eric and Annie put on their counseling hats when a very pregnant Julie appears on their doorstep prepared to leave her new husband Hank. Eric decides to take Hank out to dinner to discuss their issues. While they are at dinner, a very pregnant Julie goes into early labor. Unable to transport her to the hospital because Simon and Mary are out to dinner and Lucy is on a date, Annie does her best to calm Julie down. Hank and Eric return to the house just in time for the birth. Julie delivers a baby girl. Grateful for Eric's effort, Julie names the baby after him: Erica. Meanwhile, Lucy is disappointed when her date expects her to be 'the man', and Simon attracts the attention of an older female admirer.

Mary and her basketball teammates are upset when their high school coach imposes a lockout on the season, citing that their studies should be top priority. When the school calls a meeting to discuss the situation, Eric and Annie support the coach's concerns and decisions. Outraged by the apparent betrayal, Mary and some members of the team break into the gym and vandalize it. They are soon caught by the police and are arrested. Meanwhile, sparks fly when Simon is caught making a lewd hand gesture in front of the school, and is busted. Also, Matt contemplates returning home and Ruthie obsesses about being one of the guys.

The Camden family rallies together after Mary's arrest. Mary truly learns the consequences of her actions after she learns that she is losing her scholarship to college, faces possible school expulsion and jail time. Eric and Annie enlist the help of a lawyer who manages to get Mary enrolled in a community service program. Simon and Ruthie feel overwhelming pangs of guilt for having some knowlege of Mary's intentions and not telling their parients about it. Simon and Ruthie decide to visit many different houses of worship to attain atonement. Also, Matt moves back home to help with the family, but soon realizes he needs to live on his own.

After Eric receives a mysterious check of $20,000, he learns that the gift was from one of his parishioners who was a World War 2 internment camp survivor. When he hears that the woman has never been able cope from her internment experience, Eric helps her come to terms with the pain. Meanwhile, Ruthie learns a valuable lesson about the meaning of friendship when bribing a classmate. Matt and Shana have a miscommunication about laundry that sends their relationship temporarily into a tailspin. Simon is woeful over the injustices of the world, and Mary adjusts to her lower social status at school.

In order to get extra credit, Simon volunteers to paint a holiday mural with a few good guys in his school. The other volunteers don't like Simon because they are inhaling paint fumes and are afraid he will report them. When one of the boys winds up in the hospital, Simon is accused of providing the paint. After he confronts the boy, the boy decides to confess everything to his parents. Meanwhile, Mary is suddenly thrilled about her community service after she meets the man of her dreams: Robbie Palmer. Eric and Annie are hesitant to allow Mary to pursue a relationship because of her punishment, but do allow Robbie to call her. Matt is up in arms when he learns that Shana is transferring to NYU and that his father provided a reference without his knowledge, and Ruthie wins first prize in her art-school project: a sculpture of the Camden family noses.

When Ginger pays the Camden family a visit, she informs Eric and Annie that her father is in the early stages of Alzheimer's Disease. At first, Annie can't believe it, but after observing him in the backyard and not paying attention to a fire in the barbecue, Annie realizes the truth. Meanwhile, Mary and Eric can't see eye-to-eye on her relationship with Robbie, but they soon agree to compromise. When Mary informs Robbie of the plan, he tells her that it won't work between them. Fortunately for Mary, Robbie changes his mind after talking to Eric in the local grocery market. Also, Lucy gets into trouble after blowing off a Habitat for Humanity project to go on a date, and is caught. Meanwhile, Matt is consumed with depression due to Shana's upcoming move to New York. By this, Matt pays no attention to Simon, who just wants to spend time with his big brother. Also, Ruthie makes a vast millenium preparations until Eric provides her with a more grounded perspective.

Annie decides to take a much-needed break from the family and heads to the beach on a solo trip to get some rest, leaving Eric (Mr. Mom) in charge of the large household. Meanwhile, Matt must relunctantly say goodbye to Shana as she leaves for NYU. Mary impatiently waits for Robbie to call her. Also, Lucy realizes that she may be interested in the wrong guy, and Simon learns some tips from his sisters on how to treat a girl.

Eric and Annie reluctantly allow Mary to go out with Robbie, on the condition that they double date with his younger brother Rick (guest-star, Lance Bass, ""N'SYNC"") with Lucy. Meanwhile, Simon and Nigel buy several packs of cigarettes for a class project to prove how easy it is for children to buy tobacco. Also, Ruthie works out her own secretive science project and John invites some female neighbors over for dinner to take Matt's mind off of Shana.

Reverend Camden helps a new family in the congregation who has a son suffering from Tourette's Syndrome. With the assistance of Simon, Simon sticks up for the boy at school when bullies pick on him. Meanwhile, Annie takes matters into her own hands when she horrifyingly learns from Lucy that Ruthie's teacher has reportedly been calling her ""stupid."" Simon unknowingly hurts Mary's feelings with something he said to her earlier, and Matt puts his girlfriend Shana on the silent treatment when he contemplates calling things off.

It's Valentine's Day and the Camden's are celebrating the day of love with a special party in honor of the twins first birthday. Eric and Annie fret over how to make the babies birthday a memorable one, while the rest of the family learn different ways of exchanging love on Cupid's Day. After finally gaining her parent's trust, Mary is allowed to spend a romantic dinner with Robbie, only to learn he has ulterior motives. Meanwhile, Simon and Deena confess to their parent's that they've given each other love bites. Also, Matt welcomes his ex-girlfriend Heather back into his life, threatening his relationship with Shana.

Reverend Camden encourages his congregation and his family to trust in prayer. Lucy gets upset when people in the public thought of her as a disgusting teen mother when she takes the twins for a walk. Mary is praying that she will be able to get back together with Robbie even after what he did. Simon prays that he can see Deena soon and be on her parent's good side again even after giving her a hickey. Eric tries to locate a child who wrote an inspiring letter to him, but was left unanimous.

Eric Camden finds himself on a hung jury of a case that he considers ""open and shut,"" only to realize that he must help the other jurors regain their faith in the legal process in order to reach a fair verdict. Meanwhile, the other Camden's are suffering their own wrong doings as Annie and Ruthie ponder whether two wrongs make a right. Mary becomes in debt with Lucy after accidently giving her a black eye. Also, Simon and Deena realize that saying ""sorry"" can't turn back time, and Matt learns how important one person's voice can be.

After Mary dreams about playing basketball with the Los Angeles Laker's players, she receives an unexpected call from her coach. Mary gets her hopes up that she may be drafted by the WNBA after high school. Meanwhile, Eric and Annie get their feelings hurt after hearing Simon and Lucy, that they would'nt want to be a minister or a stay-at-home mom like they are. By this, Eric and Annie decide to spend more time with the kids to explain their roles that they've chosen in life.

Rev. Eric Camden counsels a sexually molested girl to help her express the rage and pain she's been hiding from her family. This dark secret that Mary knows about weighs in on her, which brings her to open up to Lucy. Meanwhile, Simon and Ruthie learn the power of communication with their friends and classmates. Also, Matt helps Hank reveal an important personal secret to Julie before his mother visits.

Eric and Annie are excited to learn that their family is being profiled in their local newspaper, until the reporter interviews the kids and gets more of an expose for the innocuous story than he was expecting. Meanwhile, a co-worker slanders Matt's reputation at work. Matt's roommate, John confronts a politician for misquoting an African American inspirational leader. Also, a classmate of Ruthie's plagiarizes one of her stories for a class competition. Inspirational gospel singer Sandi Patty (""Artist of My Soul"") guest-stars in a cameo role.

Eric and Annie must deal with the emotional fallout as they learn about their kids tumultuous love lives. Mary upsets her parents by announcing that not only has she decided to skip college in the fall, but she is getting back together with Robbie. Matt is forced to choose between his girlfriend Shana (who has moved back to Glenoak for the summer) or his ex-flame Heather, who confesses that she still loves him. Lucy dates Robbie's cute brother Ronald, disappointing Andrew Nayloss who still harbors feelings for her. Also, Simon gets dumped by Deena and Ruthie takes advantage of her new boyfriend.

In the fourth season finale, Simon finds out the real reason why Deena wants to break up with him. Also Ruthie does her best to get back together with her old boyfriend Burt, while Lucy also tries to go after an old flame: Andrew Nayloss. Mary decides to take things slow with her relationship with Robbie and her life. Matt and Shana break up their relationship, but reconciles with Heather. At the end of the show, it shows Matt and Heather may have gotten married- but didn't.