There’s Maddie, a lawyer, and Ben, a hotel manager, two career-oriented people who are head-over-heels in love. Both in their 30s, they’ve been together for nine years but never felt the need to get married. Then there’s Mia, Maddie’s younger sister, a free spirit and creator of a paperless web invitation company who is in a very passionate seven-and-a-half-week-old relationship with Casey, a musician in an avant-garde metal band. Last but not least, there are the girls’ parents, Vicky and Joel, who’ve been married for 35 years. Like Mia, they’ve adopted a carpe diem sort of philosophy, and at this stage in their lives don’t feel the need to take things too seriously.
With a new baby on the way, Mia and Casey begin to realize they may need to find a bigger place to live, even though babies are "notoriously small" according to Casey. The parents-to-be will need room for things like the crib, stroller, changing table, etc. Casey's totally up for a move. He'd like to find a cool place like a big loft or a barge. Do you even need to give a security deposit to live on a flat-bottomed boat?
Ben is secretly hurt when he is left out of the Putney family's Christmas card photo; Mia and Casey ask Maddie and Ben to be the people who say ``no'' to their future child.
Casey implements a plan to avoid fights with Mia; Maddie inadvertently exposes a fault in her relationship with Ben.
Mia and Casey are having a boy!
Mia and Casey offer to give Maddie a Halloween-free party for her birthday, which falls on the same day as the holiday; Mia finds a mysterious videotape among Casey's things.
Casey's mom is coming to town for Mia's baby shower.
A high-end wedding planner tries to upstage Mia's pending nuptials.
Vicky's oven is on the fritz. That means she won't be able to cook Thanksgiving dinner. This is joyous news for those who have survived all her experimental holiday meals of years past.
Casey is excited about spending Christmas with the Putneys. His family was all about sustainable living, so he typically got things like seeds and rocks as gifts. This year will be different though. Casey's psyched to get all kinds of Christmas crap as they spend the holidays at the family lake house.
Ben breaks the news to Mia that she needs maternity pantsBen breaks the news to Mia that she needs maternity pants; Joel decides to get himself into shape when he learns that he ranks last in the fantasy husband draft; Maddie tries to impress Casey.
After Mia and Casey adopt a stray cat, the pediatrician tells them they shouldn't have the animal around the baby.
Casey's Valentine's Day plans for Mia inspire Ben and Joel to break their rule of never buying expensive gifts for their ladies.
Before a job interview, Casey borrows a leather jacket that has a history of bringing the wearer bad luck.
Ben learns the new owner of his favorite bar is New York Yankee Nick Swisher, whom Ben once prevented from catching a fly ball; Maddie and Mia resist accompanying Vicky to a charity event.
Casey's ex-girlfriend wants the couch she loaned him when they were still together; Maddie updates Vicky and Joel's wills.
Maddie lies about getting laid off from the law firm; Mia and Casey suspect there is a hidden message in the children's books Vicky donated to them.
Maddie gets a feeling that the story Mia tells about how she and Casey met is not true.
After discovering Mia can't dance very well, Casey tries to conceal his skills; Ben runs into Larry King and asks him for relationship advice.
Mia and Casey try to reschedule their wedding until after their baby is born; Ben learns that Joel is worried about crying during his wedding toast.
Joel tries to use his bargaining skills to get Mia the baby stroller of her dreams; Maddie worries she's losing her passion to be a lawyer.
Mia and Casey decide to wed before the baby is born, but with Mia already in labor, it takes everyone's help to pull it off.