Robbie's apparently firm happiness with Joy kindles envy in Matt, who is now so in love with wedding plans that he vows that his next steady date must be *the one*. Being commandeered into clinic duty, Matt misses his date with a promising candidate but he also meets a fellow med student, Sarah Glass, daughter of Rabbi Richard Glass. Sarah insists that they must meet each other's parents. Although both parental pairs plead against a mixed-religions marriage, the lovebirds soldier on.

Matt has married Rabbi Glass' daughter Sarah after one date. Robbie is mildly amused at the family's speculations and how they're worrying about whether Matt 'was dumber than Mary with Wilson'. Only Ruthie finds out, answering when Matt calls, but he swears her to secrecy. Meanwhile, Matt and Sarah go tell her parents first, but at the last moment she pretends they just got engaged, a lie they must now extend to the Camden home, where the 'news' only adds to the mounting stress.

Level-headed Robbie is the only one intentionally left home to babysit the twins when the Camdens accept a first dinner invitation at humorist Rabbi Glass's home. Mary beats Lucy to the punch faking illness so she can escape the event and try to seduce Robbie away from Joy. Simon takes his half-Jewish friend Morris along, but he fails miserably as a good example of someone from a mixed-faith household: he has no clue about the Sabbath or other Jewish traditions. Eric loses it completely when Matt says he's considering converting to Judaism, but they make up during a synagogue service.

Matt ignores at his peril Robbie and Simon's warning not to believe a girl's claim she needs no gift, especially concerning the diamond engagement ring. Eric's solution within budget, industrial imitation, is 'welcomed' even more bitter, until an heirloom is passed on. Lucy flew along to Buffalo with Mary to 'pick up her stuff', but discovers aboard she wants another shot at Ben. After provoking airport security, Lucy gets an instant crush on gallant, hot cop Kevin Kinkirk. She arranges a double-date with his brother, who turns out to be none other then Ben, who is however most suspicious of record-fickle Mary until Kevin gives the decisive push.

The Camdens are surprised by the arrival of Mary with her new guy Ben and his cop brother Kevin, and with her new flight-attendant job that enabled their cheap flights. While Lucy gets close to Kevin, Eric still obsesses over Matt's secret and Robbie and Ruthie still help keep it. Eric neglects his counseling appointment with the elderly Tallridges whose adult son Jerry has 'suddenly' moved out, yet that's just what will inspire him.

Annie discovers Ruthie is writing to a Marine fighting in Afghanistan as part of a school project. The Camden family read what Ruthie has written to her pen pal about their lives and in turn learn about a Marine who so bravely has left his wife and son to fight in the war against terror. When Ruthie fails to get a response email at school and Eric hears about a helicopter going down killing two people he contacts the Colonel.

Preparations for Matt and Sarah's wedding are being made and things aren't going the way Eric or Annie planned. Matt decides he will convert to Judaism after a discussion with Sarah's dad who convinces Matt that he can convert on the wedding day much to Eric's dismay. Annie panics when Sarah's mother tells her to expect 100 kosher guests to her backyard pot luck dinner. Ruthie and Simon begin to resent Robbie being in the house. Ruthie wants her bedroom back forcing Robbie out now that Matt will be moving out and Simon gets upset that Matt chooses Robbie to be his best man and Sam and David call for Robbie instead of him. Lucy gets upset that Kevin won't come to Glen Oak for Matt's wedding and Ben decides to propose to Mary after Mary starts giving him the cold shoulder. Eric and Sarah's dad the Rabbi go head to head and it seems Matt and Sarah's wedding won't go ahead after all.

The Camden family gather together for Matt and Sarah's wedding. Eric and the Rabbi make amends while Ben and Kevin decide to go to Glen Oak to pursue Mary and Lucy. Ruthie and Simon sort out their issues with Robbie.

Eric has double bypass surgery and most of the family waits for results at the hospital. Ruthie stays home to watch the twins. Lucy tells her parents she is ready to accept a wedding proposal, but Kevin is no longer ready to propose.

Chandler's father is dying. Eric tries to get Chandler and his father to talk before he dies. Simon asks Cecilia to the prom. Ruthie has problems but does not want to talk about it. Mary has news for her father. Sarah thinks she is pregnant.

When Matt and Sarah begin training at the hospital in New York, Matt finds answering questions and performing procedures easy while the other students struggle.

Lucy thinks Kevin's partner is keeping secrets from him, such as she is trying to become a detective. Matt is having problems in his marriage. Martin learns that everyone thinks he is having sex with Cecilia.

Cecilia breaks up with Martin because she wants to be with Simon. Matt continues to run into a former girlfriend and is concerned about his marriage falling apart. Ruthie's foreign exchange student visits and is now living with the Camdens.

With Thanksgiving approaching, everyone seems to be planning something different. Lucy wants to host the big meal, Simon wants to stay at college, Mary is staying in Puerto Rico, and the others also have different plans. Annie is upset.

Annie loathes receiving an invitation to Simon's 'disaster' wedding to Rose in May, until she realizes that's the same day as Matt and Sarah's med-school graduation. Neither group will even consider another date, arguing that the other event is less important or troublesome. Ruthie considers taking a summer poetry course in Scotland to be with her ex Peter, but Eric won't pay and the phone-bill hits hard. Kevin plants the romantic idea of eloping. Rose's jealous ex Bert grills Simon about his mystery girlfriend and questions his commitment; Annie finds out and teams up with Bert, who talks Rose out of eloping as the Camdens would ruin this by attending. Yet the changes of plans and the truths that turn up inspire surprising changes of heart.

Annie and Eric are delighted with Matt and Sarah's surprise visit in time for Simon's wedding--and not just because they announce they're expecting. Simon is relieved that he and Rose aren't expecting, therefore marrying purely for love; but the next minute he gets cold feet, at which Lucy eagerly pokes. More visitors, like Matt's one-time bride-to-be Heather, stir further reminiscing and speculations; Rose's ex Umberto even asks Eric's permission to sabotage the wedding. The big day is full of surprises, including from Matt and Carlos.