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.

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.

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.

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.

There is cause for alarm when the Camden's disapprove of Simon's new group of friends, one of whom insults Annie and Lucy with his chauvinistic remarks. Norton, the kid that Simon befriends is a fan of violent rap whose negative attitude towards women seems to be influenced by misogynist lyrics. At the same time, Eric and Annie confront Simon about his newfound interest in rap music and somewhat misogynist attitude towards women. Heather gets back in touch with Matt, but Matt is unsure of her intentions. He then finds out that she is dating someone else AGAIN!

Despite the disapproval from the rest of the family and his own hesitations, Eric takes in Mary's ex-boyfriend Robbie Palmer (Adam LaVorgna) to live with the Camden's for the night after learning that he's homeless. Matt also shows up unexpectedly after being kicked out of his apartment by John, who needs quality time with his girlfriend. Meanwhile, Mary calls home again and hears Robbie's voice on the other end and assumes he's dating Lucy now. Also, John proposes to his girlfriend Priscilla in front of Matt.

A month has passed since Eric invited Mary's ex-boyfriend to stay with the Camden's until he got on his feet. Robbie happily continues to act as a member of the household--- and it's driving Annie crazy. Robbie is Eric's latest 'project', Ruthie's new best friend, recipient of Simon's financial advice, and according to Mary, Lucy's boyfriend. He's even cooking and folding laundry (the wrong way!). Frustrated and emotionally strained, Annie starts to think nobody needs a mother anymore. Also, Matt also feels unneeded from the family due to Robbie and pays an unexpected visit to Heather and her new boyfriend.

As Annie plans a mysterious day of cleaning as Eric discovers the shocking news that Mary ran away from ""The Colonel""'s to come back home because of a devious scheme she had with Robbie and freaks out. Eric is convinced that more trouble is brewing and goes to insane lengths to find answers. In reality, Mary is heading home for a huge surprise birthday party for Eric, attended by all the people whose lives he's changed for the better in the past few years. Chores at home are interrupted, however, when Ruthie discovers Frankie and Johnny's baby, Mercy at the Camden front doorstep. Meanwhile, Lucy stays with her friend Mike's (guest-star Jeremy Lelliot) near catatonic mother for the day, and drops a proverbial bomb on Lucy. Also, Matt and Simon try to figure out why they delivered Mrs. Bink (guest-star Eileen Brennan) to the hospital.

After their lackluster attempt at kissing, Mike (guest-star Jeremy Lelliot) and Lucy agree to be friends and to fix each other up on dates--- but the plan bothers Lucy more than she anticipated. Meanwhile, Matt's in a huff over John and Robbie's newfound friendship and feels slighted by the family. Eric also continues to feel alienated from his family when they keep going to Annie for advice. Also, Annie feels slighted when Ruthie plays an un-funny joke when the twins recognize her as their ""mama"".

Mary's feelings for Robbie resurface when she inadvertently finds out he has a secret date for Valentine's Day, and the whole family schemes to uncover the mystery woman. Meanwhile, with the exception of Lucy who has a date with Jeremy, the other Camden kids feel deflated when their Valentine's plans fall through and they end up stuck at home celebrating Sam and David's second birthday. Lucy and Jeremy's first date does not go as expected as they both keep on running into Lucy's ex-boyfriends. Although all's well that ends well by the end of the episode for everyone.

Although Robbie is just as nervous as everyone else, his presence in the house during Mary's weekend stay causes a great deal of concern among the Camden's. Matt and Lucy are especially suspicious after Lucy accidently finds a condom in a misplaced wallet. Imagine their surprise when they learn that the provocative prophylactic belongs to Simon--- who just so happens to be spending the evening with his new lady friend, Sasha.

Robbie is ecstatic when his long-lost father (guest-star Alan Thicke) who is a dead-beat dad appears out of the blue. Although, Eric and Annie distrust the dead-beat dad's motives. He also convinces Robbie to move out with him; against Eric's wishes. Meanwhile, Ruthie turns to Mary for advice on how to get around their parents rules when wanting to buy a makeup kit that they said 'no' to. Also, a very convinced Annie worries when Lucy starts having a relationship with her friend's freewheeling ""unmotherlike"" mom. Also, Simon develops a bad attitude with his mother when not wanting to do his school work, but wants to hang out with his friends.

Matt begins to go crazy over a psychological evaluation that he is required to take for his medical-school application. Matt also notices the strange demeanor of his psychologist, which leads to a surprising twist. Meanwhile, after Ruthie gets into trouble at school for missing homeroom classes daily, she tricks Robbie into coming to talk to her principal. Simon decides he no longer wants to be together with Sasha since they have nothing in common and that she is not that intelligent, but the plan backfires on Simon. Also, Mike wants to try to be in a relationship with Lucy again, but unfortunately she turns him down since they are both on the rebound from Jeremy and Elaine. Lastly, Eric must convince a terminally ill patient to embrace life no matter what the doctors tell him.

The striking resemblance of Robbie's new friend, Marie, to Mary raises eyebrows among discerning Camdens. Annie's invitation for her to stay for dinner makes things weirder for them. Back in Buffalo, unbeknownst to Robbie, Mary accidently bumps into her old boyfriend Wilson (guest-star Andrew Keegan) and his son Billy at the train station and makes plans to meet him for the evening. Mary is unsure on whether she should tell Robbie, but confides in her family about this. They all say that she should tell Robbie about this, but decides to ignore their advice. Also, Matt meets Robbie's ex-girlfriend, Cheryl, at the restaurant where she works. He starts to have feelings for Cheryl and tries his best to try to get her to go on a date with him. His efforts work by the end, but is having a hard time telling Robbie about his interest in his ex-girlfriend.

Annie discovers that the particularly flirtatious mother of one of Lucy's friends, Serena is seeing Eric for therapy sessions. Annie strongly requests that he refers her to someone else. Annie then has to deal with the guilt over her jealousy-induced interference between the two. Also, Simon is mortified when word gets around school over the fact that he's a virgin. Annie had shared the details of Simon's sexual inexperience with his ex-girlfriend's (Sasha) mother, Rita. Meanwhile, Matt struggles about telling Robbie he's interested with his ex-girlfriend, Cheryl. Lastly, Robbie is also hiding a secret from Matt that involves his ex-girlfriend Heather.

The Glenoak Community is making a big fuss over a petition that is protesting the apparently unfair firing of one of Ruthie's teachers, Mrs. Miller at her private school. Annie's father Charles drops by at the Camden's for a visit. Annie is then surprised and shocked when she she learns she has a half-sister.

Mary returns home back to Glenoak for the summer to spend some time with her family, but fears about being together again with Robbie. Eric and Annie are recipients of what may or may not be advances from unmarried acquaintances. Simon and Deena see that they still have feelings for each other, even though she has a boyfriend. Matt agonizes over telling his family about his new relationship with Cheryl, but soon decides to tell them all. Lastly, Lucy surprises herself and others when making a proposal to Jeremy and the possibility of going to college in New York with Jeremy. Although plans change when Mary, feeling rejected by Robbie, makes a shocking declaration.

Mary tries to right a wrong by explaining to Lucy that she never had adult relations with her sister's fiance. The only problem left is trying to convince Lucy. Wilson unexpectedly drops by the Camden home from New York to see if he and Mary are really over by finding out her answer. James talks to Eric about him attempting to have an affair with Annie as Serena comes clean with Annie about her trying to have an affair with Eric. Robbie and Wilson set aside their differences so that they can talk about Mary. Matt learns a few things when it comes to Cheryl's honesty when she doesn't tell her friends that she's dating him.

Eric's stress level rises when he learns that Matt has lost his job at the hospital and is relying on his friends to find him new work. Simon is adding to Eric's tensions by pressuring him to let him get his learner's permit. At the same time, Lucy breaks off her engagement to Jeremy and just cries in her room and refuses to discuss what happened. Robbie, still longing for Mary, is moping around the house as she returns to New York to be with Wilson. Annie's behavior has Eric wondering what's going on with her and suspects she's pregnant.

Simon decides to stand up for bullied student at school only to have the boy tell him that he is going to shoot his tormentors. Robbie decides to give Ruthie a playful new nickname, but at the same time Ruthie comes up with a less-pleasant one for Lucy after breaking off her engagement to Jeremy in New York. Eric gets a visit from an old friend Merle with some family issues of her own. Mary gets serious with pursuing the career as a firefighter, but things don't turn out the way she had planned.

Simon considers dating a sixteen-year-old pregnant Sally who he meets on the bus. Annie decides to accept Robbie's offer in renting the room over the Camden's garage that both Lucy and Matt were hoping to get. A carpenter pretends to fake an injury while working on the Camden's garage and tries to sue them. Mary gets more serious with being a firefighter, mother and wife to Wilson and Billy.

Eric tries to arrange a romantic evening with Annie, but Annie keeps turning down every attempt he throws at her. At the same time, Annie takes Eric by surprise with the news that she would like to quit college and to start teaching to help get her out of her depression. Meanwhile, Simon is at risk of being fired from his new job at the pizza parlor by his excessive tardiness and discovering that waiting tables takes more people skills than he's equipped to handle. Also, Robbie sets Lucy on a date with one of his friends while Matt is concerned about a woman who keeps showing up at the clinic a lot. Lastly, Mary performs terribly in fire fighting training distracted by her consuming relationship with Wilson.

As Annie begins teaching, she inadvertently gives a student some bad advice. At the same time, Eric and Annie painfully discover how much their constant arguing is affecting the family. Lucy and Robbie finally face up to their feelings after she intentionally sabotages one of his dates out of jealousy. Cheryl goes to Eric for some guidance in her relationship with Matt, but she misinterprets the reverend's input in the matter. Simon is attracted to a girl who is dating one of his friends. Mary is left to mull over Wilson's marriage proposal and it's even more confusing when she has a romantic encounter with a fellow firefighter trainee who shows an interest in her.

Lucy and Robbie argue over who should tell Mary about their emerging relationship. Meanwhile, Matt worries that a young woman in his study group might be a victim of physical abuse at the hands of her belligerent boyfriend. Eric's sister Julie shows up at the Camden house with her toddler Erica and annoys Annie as she tries to prepare a lesson for her class. Simon meets up with Sasha and they both try to catch up on their personal lives.

Mary's sudden arrival has everyone in the family wondering what happened between her and Wilson. Only Mary knows and she's not telling. Her presence delights Annie, who goes out of her way to make her daughter comfortable, even offering her the converted garage apartment. But not everyone is happy to see her. Ruthie feels that Mary owes everyone an apology for the actions that led to her moving away.

Matt, Lucy, Simon and Ruthie are banished to the garage apartment after protesting Annie's decision to give the place to Mary, but then the roommates begin voting each member vies for sole ownership. Meanwhile, Eric and Annie are not seeing eye-to-eye on Mary's situation as she is now returning home and is wondering on what's next in her life. Robbie is nervous about meeting his new girlfriend's parents.

Mary and Lucy seek their parents for expertise in matchmaking and ask their parents to find new boyfriends for the both of them. Robbie argues with Joy about spending so much time together when she insists on seeing him right away. Simon and Matt are looking for girls using the Sam and David as adorable bait to attract women, but it doesn't go as planned. Robbie unknowingly becomes the key to finding Joy's missing younger brother Joseph when he finds a stray dog in the street that belonged to him.

Annie's father Charles shows up at the Camden household for a weekend visit as Ginger supposedly needs to get away for a bit. But Eric forgot to tell his wife about it and nearly everyone in the Camden household is too busy to spend time with the elderly man. So Grandpa Charles takes Simon to get his learner's permit for driving and they end up being the center of a televised police-pursuit. Eric lies to Annie about his plans for the day, which include a trip to Glenoak Hospital.

Annie quits her job at the private school without discussing it with Eric first and he feels completely left out. Mary tries to call Wilson and learns from his landlord that he has moved out of his apartment. Simon uses Robbie's car to practice driving and gets him in trouble when Simon smashes into Matt's car. Robbie's brother Ronald stops by at the Camden home for a visit. Mary gets an unexpected visit from Ben, the fireman she kissed. Ruthie's old teacher Ms. Riddle starts working at Ruthie's school.

St. Valentine's Day delivers a few surprises for the Camden family. A grounded Simon is asked out by a senior. Annie's attempt to surprise Eric with romantic Valentine's plans backfires and results in a big fight. Mary discovers Robbie's plans with Joy. Lucy and Mary learn that Jeremy and Wilson both have dates for Valentine's. Matt seeks his fathers help as he wants to settle down, which leads him to seek out old girlfriends as to why they're no longer together. Ruthie is hesitant to go to a party because her friend tricked her into asking out a boy she's already going out with.

Matt is determined to settle down before heading off to medical school. While in search of a woman to marry, he goes out on a date Sarah, who is the daughter of a rabbi. Ruthie tries to set her brother straight by telling him not to do anything stupid. Eventually concern grows to fear for both families as both Matt and Sarah do not come home after their second date together in less than 24 hours.

Matt stays out all night with Sarah and they secretly elope, but when facing their parents they're only able to summon the courage to say that they're engaged. A worried Annie tries to calm Eric down, who is convinced that Matt did something foolish. Meanwhile, Lucy and Mary search for Ruthie because they suspect that she knows what really happened during Matt's night out. Ruthie and Matt agree to keep the marriage a secret until a Jewish wedding in a few months.

Annie frantically cooks Jewish dishes as the Camdens prepare to head out to a Shabbat dinner at the Glasses. Simon asks Matt and Sarah if he can bring his friend Morris to the dinner. Matt agrees to allow Morris to come to the dinner as he is half Jewish. Although, that does not go as he planned as he is not very knowledgeable about his faith. Lucy and Mary play sick to try to skip the outing so they can stay home with Robbie. While home, Mary flirts with Robbie. Lastly, Eric and Annie are unable to handle everything when they are shocked to find out during dinner that Matt is considering to convert to Judaism.

Matt and Sarah argue over their wedding plans and their agreement to forego buying an engagement ring and seek Eric for advice, who isn't happy with Matt for getting engaged in the first place. Because of Eric, Matt buys Sarah a fake engagement ring. Mary and Lucy fly to Buffalo for a weekend, or at least that's what Lucy thinks as Mary makes plans of her own. At the airport, Lucy meets a police officer who invites her and Mary to double-date with him and his brother.

A startled Eric catches Mary and Lucy in the kitchen with Ben and Kevin in the middle of the night. The guys end up spending the night in the living room with Mary ad Lucy. Ben and Kevin's sister calls the house to inform Ben and Kevin that their mom is going out with a neighbor. Eric suspects that Ruthie knows a secret about Matt and Sarah and thinks they are married already. Meanwhile, an older couple seeks guidance from Eric when they can't seem to let go of their forty-four-year-old son, who has run away from home.

The Colonel drops by to tell Ruthie about the death of a soldier she has been corresponding with. Ruthie shares her letters with the family. At the memorial service, Eric asks everyone to advocate good deeds and go out into the community, as the family does.

Matt and Eric meet with Rabbi Glass to discuss wedding plans, and Eric learns that he is playing a smaller role than he had originally planned. Annie prepared for fewer guests to attend the rehearsal dinner and gets very flustered when she does not have kosher food. Ginger and Charles are prepared to fly to Glenoak, but Charles get's lost at the airport. Simon gets angry when Matt asks Robbie to be his best man. Meanwhile, Ruthie tells Robbie that she wants his room for herself after Matt moves out. Ben proposes to Mary, but he gets an unexpected answer.

Matt and Sarah grieve over Eric's decision not to attend the nuptials following his argument with Rabbi Glass over Matt's conversion to Judaism. Hoping to patch things up between their fathers, Matt and Sarah seek their mothers' help in persuading them to put aside their differences before it's too late. Ben and Kevin come to Glenoak to meet up with Mary and Lucy so that they can resolve their problems. Robbie tries to figure out why Ruthie wants him to move out of the Camden household.

Kevin is now living in the garage apartment and is madly in love with Lucy and waiting for the right time to ask Lucy to marry him. He invites his new rookie partner Roxanne over to meet Lucy who takes one look at her and flies into a jealous frenzy. Robbie is jealous of Kevin because he feels as though Kevin is like a new big brother taking over Matt's place. Robbie, who has been lamenting the departure of girlfriend Joy, may also be ready for romance when he runs into Kevin's partner Roxanne, an old classmate from 7th grade.

Ruthie is asked to babysit a chimp which lives across the street. Ruthie also invites her boyfriend over which stuns Eric. Mary desperately tries to keep her mysterious new boyfriend a secret. When he unexpectedly shows up at the Camden home, no one is more surprised than Eric to see the good-looking 40-something pilot standing in the doorway.

Simon's paid dating service is becoming profitable until Cecilia rats him out to Eric. When Mary threatens to leave home over her relationship with Jack Smith, who is twice her age, Eric confronts Jack who lets the news slip that he and Mary are relocating to Fort Lauderdale. Lastly, Kevin sets Ruthie straight on who's the adult and who's the child in this household.

Ken Smith pays a visit to Eric and Annie to accuse Mary of seducing his son. He threatens to sell the land next to the church if Mary doesn't break up with Jack. Simon finds out from Cecilla that a girl from his dating service is pregnant. Simon turns to her to try to help her. He convinces her to drop her baby off at a hospital where the baby can go for safe keeping. Lucy wonders if Kevin has ever been with another women after she catches Ben reading her journal. When Ben picks Ruthie up from school, he see's a girl making fun of her and then she makes fun of him, which leads to the vice principal calling the police.

When Eric learns that he must undergo double bypass surgery, he calls a family meeting to share the news but loses his nerve at the last minute and decides the group should go bowling instead. His odd behavior surprises everyone, especially Annie who grows more concerned when Eric's brother-in-law Hank shows up unexpectedly. Meanwhile, Robbie pesters Kevin about helping him make a parking ticket disappear. Lastly, Lucy continues to question whether Kevin has ever been with another woman.

The extended Camden clan wrestles with their emotions as they await the outcome of Eric's double bypass surgery. While under anesthesia, Eric hallucinates that he's Elvis. Lucy finally realizes that Kevin is the one and that she's ready to marry him, but he refuses to propose until Eric gives them his blessing. Simon complains to Annie about the absence of Matt and Mary during their father's health crisis. Sarah also comes to Glen Oak to wish Eric well.

Lucy is asked by a developmentally challenged friend to convince his parents to let him join a traveling troupe of puppeteers. Meanwhile, Eric is feeling low because he is stuck at home recovering from surgery and really wants to get back to work despite doctor's restrictions, so Annie asks the kids to help make him feel needed by going to him with their problems. Ruthie takes this suggestion to heart and secretly tells Eric how he should be helping everyone with their romantic entanglements. His meddling leads to chaos for everyone involved. Lastly, Kevin learns that Ben is planning to extend his temporary stay in Glenoak.

Eric is stunned to find out the church has hired a new associate pastor to help out while he recovers from his heart surgery. Meanwhile, Lucy is furious when she and Ruthie spot Kevin and Roxanne in a jewelry store--as she thinks they're picking out her engagement ring together without her. Meanwhile, Simon listens unenthusiastically as Cecilia tells him all about her new French boyfriend. Lastly, a loud, chain-smoking housekeeper sent by The Colonel arrives to provide order in the Camden household.

Eric and Rabbi Glass pay a visit to the church to spy on the new associate pastor. Meanwhile, Ruthie is in big trouble when she's caught slow dancing with her boyfriend when she's supposed to be babysitting Sam and David. Meanwhile, Lucy asks Simon to dig up some information on Roxanne during his ride-along with her and Kevin in their patrol car. Lastly, Kevin has some explaining to do to Lucy after he runs into his ex-wife.