Mia invites Maddie and Ben to meet Casey, and they think they're meeting just another in a long line of boyfriends. But Maddie realizes how serious things actually are when Mia and Casey excitedly announce that they're engaged. Surprised by the news, Maddie feels like her little sister has leapfrogged over her -- jumping ahead of her in some major, life-changing way -- and sees the light it shines on her own life choices. But reluctant to be a negative voice, she resolves to be supportive and let her parents, the critical Vicky and Joel, be the ones to object when the...
Mia and Casey go house hunting when they realize that Mia's apartment will be too small for them when the baby comes. But Casey's unusual taste in home selections concerns Mia, especially when he sets his sights on a dilapidated old firehouse. Maddie tells her to just go along with his choice because, before a man turns 27, he never knows what he wants anyway. Meanwhile, now that Joel has recently retired, the already-retired Vicky finds her husband getting on her nerves because he doesn't know how to spend his new, free time.
Everyone dreads the gimmicky Putney family Christmas photo card that Joel obsesses over every year. But Ben, who has been left out of the card despite being with Maddie for nine years, is secretly hurt when Joel invites newcomer Casey to be included, so he and Maddie devise their own rival Christmas card. Meanwhile, when Mia and Casey realize they're no good at saying "no," they ask Maddie and Ben to be the ones to say it to their future child.
When Casey and Mia have their first fight as an engaged couple, Casey implements his plan that stops all arguments cold. In an effort to help, Maddie decides to show them how arguing can actually be healthy for a relationship, but ends up exposing a fault in her own nine-year relationship with Ben. Meanwhile, the longtime married Vicky and Joel quietly resolve their arguments by simply hiding each other's things.
Maddie thinks the best way to get someone to do something is to make them think it was their idea. She makes a deal with Ben to see if he can make Vicky think that it's really her idea to stop sending frivolous emails to his workplace. Meanwhile, after the ultrasound, Mia has trouble convincing father-to-be Casey that their romantic activities will not harm their baby, so Maddie suggests Mia find some way to make Casey see her as the sexy woman he fell in love with.
It's Halloween, which is also the date of Maddie's birthday. Because Maddie feels like she can never have a real birthday -- since the holiday always steals the spotlight -- Mia and Casey offer to give her a Halloween-free party at their new home, the renovated firehouse. Ben, however, wasn't listening when Maddie told him what she wanted for a gift, so Joel tells him about what he does whenever he messes up. Meanwhile, Maddie and Vicky warn Mia that couples living together shouldn't look behind each other's "curtain," for fear they might learn things they should ...
Joel and Ben accompany Casey on a road trip to Vermont to help him move his stuff out of storage. Ben looks at the trip as an opportunity to bond with Casey; but Joel sees the road trip as his annual chance to go off -- way off - of his salt-free diet. Meanwhile, the Putney women organize Mia's baby shower, and Casey's hard-to-please mother, the earthy but rather quirky Ariel, comes for a visit. Mia goes out of her way to be accepted by her future mother-in-law, but things get heated between Vicky and Ariel when both want their grandchild to call them "Nana."
Mia and Casey are excited when Maddie gets them a meeting with one of the top wedding planners in the city -- the charming but very expensive Lorraine Ashley. But the too-good-to-be-true arrangement turns awkward when it looks like Lorraine is trying to upstage the couple's pending nuptials. Meanwhile, Ben realizes that he has been with Maddie for so long that his "flirting muscle" has gone soft.
This Thanksgiving, everyone but Vicky is relieved when her oven breaks down. For once, the rest of the family can enjoy a normal Thanksgiving dinner and won't have to endure one of her unsavory concoctions -- such as maple syrup turkey stuffed with shrimp and raisins. And while spending the holiday at Maddie's and Ben's apartment, Mia accidentally finds her late grandmother's presumably stolen ring hidden in their linen closet... Now the unmarried couple has some explaining to do.
Mia and Maddie know their parents will give them an avalanche of guilt if they don't uphold the Putney family Christmas tradition of spending the holiday together at their lake house. When Maddie finds out Mia and Casey are using their pregnancy as an excuse, she tells Vicky and Joel her own tall tale to keep from having to go.
When Mia accuses Ben of ripping her favorite pair of jeans, she drags him to the store, where he has to break the tough news to Mia... it's time for pregnancy pants. Meanwhile Joel decides to get himself into shape after he finds out he's ranked last in Vicky and her girlfriends' fantasy husband draft website, and Maddie goes to extreme lengths to impress Casey with her high regard for the U.S. Postal Service.
After parents-to-be Mia and Casey adopt a cat, the pediatrician tells them they shouldn't have a stray animal around the baby. Maddie and Ben enter into a spirited competition with Vicky and Joel, all under the impression that if one of them takes in Mr. Meow-gi, then Mia and Casey will name that couple as the baby's guardian.
Casey has big plans for his first Valentine's Day with Mia. But Ben and Joel tell him that their rule is to never buy expensive Valentine's Day gifts for their ladies because doing so would set a costly precedent. Casey goes ahead with his plans anyway, and Ben realizes that he too wants to show Maddie how he feels. When Joel finds out, he decides to compete with them no matter the cost - and gets singer/pianist Michael Feinstein to perform.
The job interview-bound Casey, unaware that bad luck always follows the wearer of a particular leather jacket, borrows it without telling anyone. Everyone recalls their own bad experience while wearing the jacket, including Ben, who accidentally dropped a blanket on New York Yankee outfielder Nick Swisher when he was trying to catch a fly ball.
Casey finds out that his ex-girlfriend wants to pick up the couch that she lent him before their breakup - the same couch that Mia and Casey are currently using. Since the Putney girls are known to be the jealous type, Ben assures Casey that he'll come up with the perfect plan to help him get rid of it without Mia knowing the real reason. Meanwhile, Maddie updates Vicky and Joel's wills, but finds they won't take her professional efforts seriously.
Maddie is ecstatic when she's told that she has made partner at her law firm. But just as soon as she tells everyone about her promotion, she gets laid off and, to save face, tells everyone she quit because she got a better job. Meanwhile, Vicky gives Mia and Casey a children's book passed down through the generations. Upon closer scrutiny, they parents-to-be wonder if there's a hidden, negative message between the lines.
On the eve of Mia and Casey's engagement party, Maddie gets a feeling that the oh so romantic and charming story Mia has been regaling everyone with about how she and Casey met isn't true; and Mia starts to doubt her sister's story that she and Ben met while building houses for the poor. Meanwhile, Vicky and Joel, who have always said they met chasing a foul ball at a baseball game, have the engagement party at their country club and realize they can save some money at the same time by promoting Joel's campaign for the club's treasurer.