Brian considers ending another dead-end relationship with his latest girlfriend. He makes a pact with Adam, his best friend since childhood, that they both break up with their respective girlfriends. But after Brian breaks up with his latest love, Adam chickens out and instead proposes to his girlfriend, Marjorie, whom Brian actually considers his own Miss Right -- a secret that he must keep to himself. Meanwhile Dave, who runs a video game business with Brian called Zap Monkey, and his stay-at-home wife of 13 years, Deena, discuss a possible venture into the world of open marriage. Brian’s fortysomething sister, Nic, and her younger husband, Angelo, are trying hard to start a family, but something’s not right and their efforts to get pregnant experience a setback. Despite all of the challenges these couples face, they can’t wait for Brian to join their “club,” though they’re not exactly sure why.
As Brian tries to put his secret feelings for Marjorie aside, Adam and Dave encourage him to live the ultimate single man’s dream by hooking up with two different women in 24 hours. Meanwhile, Marjorie experiences mixed feelings when she sees Brian moving on; Deena thinks about the possibilities of an open marriage when she meets a cute divorced dad at her daughter’s school; and in their efforts to have a baby, Nic encourages a reluctant Angelo to go to a sperm clinic.
When things go awry the day Marjorie moves into fiancé Adam’s place, she doesn’t want to interrupt him from his deposition work, so she calls on Brian for help -- forcing the two to take stock of their friendship. Meanwhile, Dave and Brian anxiously await a call from a potential client who could solve their money woes, Nic and Angelo consider their fertility options, and Deena is torn between staying home with her sick child or accepting a date from the cute divorced dad she met at her daughter’s school.
It’s Saturday and everyone wants something from Brian, but no one can find him. Brian has decided that he would rather spend the day with his new love, Lisa B (Bre Blair). Meanwhile Nicole, hopped up on her fertility hormone treatments, needs her brother to help her and Angelo with a car problem; Deena and Dave expect Brian to play “Barney” at their daughter’s birthday party; Adam, stuck planning the wedding, wants him for some guy time; and Marjorie keeps leaving messages on Brian’s phone to talk about their relationship.
Brian’s apparent interest in his new girlfriend causes Marjorie to unwittingly sabotage the relationship. Dave, who is convinced that Deena is having an affair, turns what was supposed to be a simple golf outing with the guys into a complicated stakeout to catch his wife in the act. Meanwhile, Nicole has told Deena that spouses shouldn’t keep secrets from each other, but she’s hiding from Angelo that she’s taking fertility hormone injections.
Brian and his company head to Las Vegas for an investor meeting. Catching wind of the upcoming trip, the entire gang decide to tag along and bring Majorie with them, not know about what happend between her and Brian.
Six months have passed since Brian left L.A. following a fight with Marjorie. In four days, she'll marry his best friend, Adam. Now Brian is back, and Adam isn't pleased to see him. As for Marjorie, she doesn't know what to feel. Meanwhile, Dave and Deena are in therapy following their disastrous open-marriage experiment; and Nicole is about to give birth, but misses her actor-husband, Angelo, who's making a movie in Italy.
It's Adam and Marjorie's wedding day, but she has some explaining---and soul-searching---to do over her encounter with Brian the night before. He won't let the matter drop, either. Meanwhile, best man Dave engages in some extracurricular activities with Suzanne in his office; and maid of honor Nicole gets an unwanted phone call from Angelo. Flashbacks recall New Year's Eve 2003, the night Adam---and Brian---first met Marjorie.
It has been two weeks since Adam was left at the altar, and he still blames Brian for it. Meanwhile, Nicole helps Deena try to save her marriage, while Deena reciprocates by letting a nervous Nicole practice mothering by babysitting her 1-year-old. And Deena meets Suzanne, the woman whom Dave has been having an affair, on the set of the local cable show on which Dave and Brian are appearing to promote their new video game.
To encourage each other to get over Marjorie and back out in the dating game, Brian and Adam bet to see who can get a girl first. Meanwhile, Brian adjusts to having Dave as his new roommate after Deena kicks him out of the house for having an affair; Nicole prepares for her baby shower, as well as a surprise guest; and the future of Zap Monkey is in jeopardy, which causes a financially-strapped Brian to try anything and everything to save the company.
At Angelo's funeral, the friends give loving tributes and recall fond memories of Angelo while they marvel at Nicole's strength. However, they soon realize she may not be handling this as well as she seems to be. Meanwhile, Brian's dad, Michael, confronts Brian about his plans now that Zap Monkey has folded, Dave and Deena discuss getting a divorce, and Adam continues to connect with Summer, the stripper he met at his bachelor party.
In need of money, Brian starts working at his father's high-end real estate firm. Sparks fly when he meets the company's top agent, the beautiful Bridget. Meanwhile Dave begins a new job as well, and he and Deena work out a unique child custody arrangement; Adam's relationship with Summer may mean problems with his professional future; and Nicole moves on despite the grief after losing her husband.
Adam and Heather start to second-guess their recent actions; Dave suggests a way for Brian to spark the interest of the reluctant Bridget. Nicole immerses herself in Deena's fledgling cupcake business to distract her from her grief; and Deena meets a rich client who might be interested in more than her cupcakes.
Brian and his dad are driven apart by a secret involving Bridget. Jimmy runs a criminal-record check on Heather; Deena decides to go out with T.K. following a couple of "practice dates"; and Dave lends moral support to Nicole when he accompanies her to a screening of Angelo's last movie, where she meets a mysterious woman with a connection to her late husband.
Brian tries to stay away from Bridget once he learns that she and his father once had an affair, but she's not making it easy. For comfort, he considers reconnecting with his mother, whom he hasn't seen in a while. Meanwhile, Brian and Adam are sentenced to community service at a homeless shelter for the fight they had at Ivy's bar; the very pregnant Nicole goes to some humorous extremes to induce labor; Deena goes on a date with her rich client, and Dave goes on a date with a much younger girl.
When Brian's dad decides to take the real estate company away on a retreat, Brian and Bridget gradually get closer. Meanwhile, after Adam and Dave make an awkward visit to the strip club where Heather works, Adam wants his new wife to give up her job, and Nicole promises both Dave and Deena that they can accompany her when she goes into labor, but neither is willing to give up the spot to the other.
Brian and Bridget have the conversation about their ex-relationships, but Brian doesn't include Marjorie. Adam and Heather have to deal with an overzealous ex-client of Heathers, and Nicole sets up a photo shoot to promote Deena's fledgling cupcake business. Meanwhile, Dave and Deena make a startling discovery about their one-year-old daughter, which brings to town a visitor from the friends' not-so-distant past.
Marjorie helps treat Deena and Dave's hearing-impaired 1-year-old, and her presence in L.A. leads to tension between Adam and Heather. It could affect Brian and Bridget as well, especially considering they have been a couple for six weeks, which is about as long as Brian has ever been able to maintain a relationship. Meanwhile, Nicole is having a hard time finding a nanny.
Brian invites the gang---and Bridget---to his father's soon-to-be-sold lake house in an effort to make her feel like part of the group; Dave and Deena grapple with their decision about their daughter's ear surgery; and Adam tries to sort out his feelings for Heather and Marjorie.
Now that both Brian and Bridget have lost their real estate jobs and she has lost her condo, she moves into Brian's apartment, where he has taken a job as the building manager. Brian helps two extremely attractive women, Laura and Stephanie, move into the apartment downstairs. Meanwhile, Deena and Dave discuss whether he should move back home to help with their daughter's ear surgery recovery, Nicole fantasizes about Jamie, her "manny," and now that he's separated, Adam takes a vow of celibacy.
Dave is surprised to see that his new boss, Natasha, turns out to be his former intern. She has re-invented herself from being overweight and non-descript into a sexy, manipulative and shrewd businesswoman. While Bridget is away on a business trip, Brian's downstairs neighbors, Laura and Stephanie, convince him to let them use his apartment for a party that turns raucous. Meanwhile, the still-celibate Adam continues to pursue his law partnership, Dave moves into the guest room back home and Nicole has an erotic dream about her "manny."
While Brian wonders if his relationship with Bridget is the right thing, Laura senses that all is not right between the couple. Natashas favoritism toward Brian becomes apparent when she asks him and not Dave -- to coordinate a major presentation for some Japanese clients. Meanwhile, now that Adam has made partner, he breaks his celibacy rule and goes out on a date with Stephanie. And after Nicole and her manny, Jamie, share a kiss, Nicole no longer thinks he is gay.
Deena's mother, Frankie, comes for a visit and, like everyone else, is unaware that Dave and Deena are back together. Now that Brian has broken up with Bridget, he gets separate invitations from his two attractive downstairs neighbors. Meanwhile, against Natasha's wishes, Brian assigns a big presentation to Dave; Adam and Nicole deal with the aftermath of their unexpected tryst; Dave gets into a fist fight with Deena's ex-lover; and the friends get a surprise when they visit Ivy and Jimmy's home for the first time.
After an embarrassing photo of Brian with fledgling actress Stephanie runs in the tabloids, she's instructed by her manager not to be seen in public with him. So Laura is secretly delighted when Stephanie invites her to go along with them to a hot Hollywood party and act as Brian's date. Meanwhile Deena's new cupcake store struggles until business partner Nicole comes up with a unique way to get more customers; Natasha sets the parameters for her relationship with Adam; and it's time for Deena and Dave to decide if they're going to sign their divorce papers.
Dave and Deena's plans for a secret getaway to renew their wedding vows turns chaotic. Meanwhile, Brian and Adam's babysitting duties for Dave and Deena's daughters are interrupted when Natasha shows up with a work emergency. Brian calls on Stephanie to look after the girls, but when a crisis occurs, he realizes that Laura is the one he should have asked to help. And after Nicole and Deena's Icing on the Cupcake store starts getting great press, an overwhelmed Nicole finds herself alone and without any help to tend to the many new customers.