Annie is livid when her father brings along his girlfriend on a weeklong visit; Mary and Matt pursue new romantic interests; Lucy wants to find out if blondes really have more fun.

Mary undergoes knee surgery, while Matt learns that Michael Towner was the hit-and-run driver; Wilson reveals the truth about Billy to Eric.

Eric and Annie decide to renew their vows; a widow seeks Eric's help to confront the juvenile who murdered her husband; Mary is reluctant to put down her crutches.

The Camden kids get a lesson in love as Mary decides to call it a quits with Wilson. Simon is obsessed with getting his first girlfriend, while Ruthie learns the do's and don'ts of kissing on the school playground. Matt receives devastating news from his girlfriend Heather, which leads him on a long journey to Philadelphia. Meanwhile, Lucy laments over being single until she accidently gets close to the school hunk.

Simon wants to buy the perfect gift for Deena because its their three month anniversary, but it ends up consuming his time which annoys his friend, Nigel, who's visiting. Rod (Lucy's ex-boyfriend) is spending time at the Camden's home because his mother died and doesn't want to face his father as he's angry with him. Heather is back in town, and she tells Matt that she's engaged. Meanwhile, Dr. Hasting's---the doctor who almost killed Matt when he was born, works at Glen Oak Hospital and Annie is not thrilled, especially with the possibility that he may deliver her twin babies. Mary tells everyone that she's back with Wilson, but it's not true. She made it up to get attention from guys. Lastly, Michael Towner, who hitted Mary with his car two years ago calls her.

Eric worries about Matt as Heather's wedding approaches. Eric learns that his sister Julie is dating Dr. Hastings (the doctor who delivered the twins and almost killed Matt at birth) without telling him or the family. Also, Lucy and Simon are both in their awkward love triangle between all of their two best friends and lovers. Ruthie wants to be a bridesmaid and a bride at Heather's wedding.

In the third season finale, Eric counsels an engaged couple facing difficulties. Mary, Lucy and Simon learn the repercussions of forbidden love, especially Simon when he is caught in his bedroom alone with Deena kissing near his bed. Julie gets married to Dr. Hastings (Hank) and learns that she's pregnant. Also, Heather breaks up with her fiance after she learns he was cheating on her with another woman. Matt tries to save his relationship with Shana after he ran off with Heather, and does this through his pleading of forgiveness.

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.

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.

In the fifth season-opener, big changes are afoot in the Camden household this fall as Eric is distressed by the fact that his daughter Mary has opted to postpone college in favor of a little soul searching and the glory of minimum wage. Mary decides to buy a car. Also, Annie leaves Eric with a handful at home so she can complete her teaching degree. Meanwhile, Simon attempts to fit in with the treacherous terrain of high school, and Lucy looks forward to ruling the school as a senior. Lucy can't wait to start a relationship with Andrew Nayloss, except he hasn't come back from summer vacation yet. Meanwhile, Heather and Matt's on-again-off-again relationship threatens to be off-again--- permanently. Matt considers the pre-med track at college and Ruthie learns that she will have to spend another year with her despised third grade teacher, Ms. Riddle.

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!

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.

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.

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.

It's Camden chaos all around when Matt, who is having problems in his marriage to Sarah, returns to Glenoak for a visit and runs into his ex-girlfriend Heather on his flight to Glenoak. Simon unexpectedly announces he's coming home for the summer.

Also, Lucy sets out to discover why Roxanne is suddenly too busy to hang out with her as she's convinced that Roxanne is secretly trying to become a detective behind Kevin's back. Ruthie keeps a secret about a fellow student from her parents. Lastly, Martin learns that his baseball teammates think he's having sex with Cecilia.

The Camden chaos continues with Matt, who is trying to salvage his marriage, questioning whether he still has feelings for his ex-girlfriend Heather; Simon's return to Glenoak creates conflicted feelings for his ex-girlfriend Cecilia, who is torn between her feelings for Simon and her current boyfriend Martin; Ruthie's foreign exchange student friend Maria, appears to be making the moves on Ruthie's boyfriend Peter; and grandparents-to-be Eric and Annie hop a plane for New York, despite Mary's repeated pleas for her family to stay away.

Simon and Rose prepare for their wedding day, despite speculation that it is not the right decision. Annie and Eric go through countless scenarios in their minds as they reflect on how the wedding will actually turn out.Meanwhile, Rose's former boyfriend shows up unexpectedly. Ruthie considers studying in Scotland over the summer. Kevin, Lucy, Matt, and Sarah all have life-changing news, if only they can find the perfect time to share it with the family...and the surprises don't stop there!