Pete (Paul Rudd) and Debbie (Leslie Mann) are having shower sex. Debbie is amazed at how good it is and Pete quips that his secret is Viagra. She immediately stops and gets out of the shower, asking if he can’t get hard for her without the pill. Pete insists that he just thought it would make it better thinking it would be a good idea to “supersize” it for Debbie’s birthday but she thinks it is the worst present ever. She asks where he got the pill and he says that his friend Barry gave it to him. He insists that it was just for her fortieth but she won’t have it Fuck Forty.
Pete sneaks into their children’s bedrooms to wake Sadie (Maude Apatow) and Charlotte (Iris Apatow). They hastily prepare the kitchen for Debbie while she is in the bathroom smoking. She quickly covers it up with perfume, bath oils, and other items to hide the smell of smoke. When she steps into the kitchen the family sings her Happy Birthday and presents her with a cake: Happy 38th Birthday! While Sadie and Charlotte argue in the living room, Pete asks Debbie what she’d like to do today: Forty is a milestone and Pete will be turning Forty in a few days. He teases her for being insecure about their age and lying about it. She asks him what he got her for her birthday and Pete is stumped she told him not to get anything. Debbie insists that Pete should have gotten her a surprise gift it’s her fortieth birthday!
As Debbie gets ready to go work out, Pete asks her if she’s gotten a call from her father. She tells him no, but it’s no surprise. Debbie goes running with her friend Barb (Annie Mumolo) and their personal trainer, Jason (Jason Segel). He’s surprised to hear that Pete needed to use Viagra to have sex with Debbie and asks if they’ve been having issues. Barb chips in that getting rid of sex was the best decision she made for her marriage: no more fighting which explains to Jason why Barb always looks like she’s in pain. Debbie thinks that Jason has been alone for too long and needs a family, but he insists that he’s going to “Clooney it.”
After a nice long bicycle ride with his friends, Pete and Barry (Robert Smigel) stop to get some food. Barry points out that you never tell the woman you’re with that you’re using Viagra. Pete says that he and Debbie are just in a phase where they hate everything the other says but Barry assures him they just need to ride it out. Pete wonders if other men fantasize about what it would be like if their wife died and Barry admits he has but it’s got to be peaceful since “this is the mother of your children.” They riff for a bit about how single women love widowers sine they’re the exact opposite of a divorcé.
Afterwards Pete, Debbie, and the kids are driving towards Debbie’s store. Pete objects to Debbie having to go in and check on the store on her birthday but Debbie wants to make sure her employees are getting along harmoniously. Jodi (Charlyne Yi) and Desi (Megan Fox), Debbie’s two employees, don’t get along very well. Debbie asks Jodi to do an inventory for an upcoming sale and to really pay attention since they have $12K unaccounted for. Jodi insists that it must be Desi either because she’s stupid or stealing. Debbie points out that Desi brought in $9K last month while Jodi only brought in 22 hundred. Pete walks over to Debbie and says he thinks Desi isn’t wearing underwear. Debbie scolds him for looking while Desi impresses a client into buying anything she recommends.
Back at home, Pete has been in the bathroom a long time playing scrabble on his iPad. Debbie asks why he’s gone to the bathroom four times already is his instinct to escape? She angrily grabs his iPad and walks away.
That night, Pete is at a small nightclub supporting one of his clients. Debbie is in the audience and watches Pete’s artist sing but she quickly gets bored. When they drive home, she confesses she just doesn’t like the music. She asks when he’s going to be ready to do his job and sign a talentless little monkey so that they’ll be able to eat. Pete defends his artistic sensibilities saying that all he needs to do is sell 10K records and they’ll be fine. When they get home, Pete and Debbie go into Sadie’s room to determine what is hip. Sadie’s pop music presses Debbie’s point and when Pete puts on classic rock, it tanks with the girls. When they point out he’s the only one who enjoys it, he mumbles that he wishes one of them had a dick.
Morning: Debbie gets the kids ready for school. She drives Sadie and Charlotte off while Pete goes to work. At the school, a woman with a young girl asks to set up a play date with Charlotte and her daughter but Charlotte is against it. When she drops Charlotte off, Charlotte’s teacher says that Debbie needs to bring Charlotte to school on time as Charlotte requires extra time to settle down. Debbie points out that she is on time but the teacher insists that she needs to be early to be on time.
At work, Pete’s accountant makes it clear that the business is in danger. Pete needs to consider selling the family’s house to stay afloat. He goes out to deal with his two employees, Ronnie (Chris O’Dowd) and Cat (Lena Dunham), who are trying to figure out how to sell their client. Pete makes it clear that they don’t have the money to launch a new act so they have to make their current ones work.
That evening, Debbie gives Pete a list of things they need to do change on. She wants them to be a healthy, happy couple so they’ll need to give up all their bad habits smoking, junk food, being negative in order to make the best out of their next 20 years together. Debbie goes over security footage from the store and sees Desi and her boyfriend having sex in the middle of the day. She comments that she misses that spontaneity and passion. Pete farts grossing Debbie out.
Sadie is doing homework and Charlotte keeps distracting her desperate to have someone to play with. Unfortunately, Sadie is busy and tells Charlotte to get out. Charlotte retorts that Sadie hasn’t been fun since her body started changing.
The couple begins their list of changes by getting check-ups from their doctors. At Debbie’s gynecologist office, there appears to be a mix-up with Debbie’s forms as each has a different date of birth on it. The doctor politely writes her date of birth as two years later than what she put down. The next morning, Debbie is craving a cigarette…so she offers to give Pete a blowjob. Unfortunately, the kids need to get to school and start banging on the door, ruing the couple’s fun.
Pete arrives at his father’s house and knocks on the door. Larry (Albert Brooks) opens up and invites Pete in, while Pete’s younger brothers scurry around the house. Pete makes it clear that his business is going through some growing pains and it’s getting harder and harder to help support Larry’s family in addition to his own. Larry stops Pete to tell him about how Pete’s mother wanted to get an abortion but Larry said “hey, let’s grab some pizza and if you still want to abort it at the end of lunch we’ll do it.” Larry guilts Pete into continuing to support him and his brothers.
Debbie goes to visit her father, Oliver (John Lithgow), at a restaurant. He asks how Pete is faring at Sony and it becomes clear that the two haven’t talked in a long time. He shows her photos of his new family before leaving to go to the bathroom leaving Debbie to rifle through his phone and look at her younger siblings.
When Debbie returns home, she cooks an alternative, tofu-friendly meal for the family and proposes more changes: no more Wi-Fi and limited internet access under parental supervision. Sadie gets pissed at this and leaves the table, proclaiming that she needs the Wi-Fi to do her homework. Pete can’t help but point out that Sadie has a point.
Pete and Debbie escape for a weekend, leaving the kids with Jodi. They eat pot cookies, have sex, and just have fun. They discuss how they get so angry with one another and both confess to fantasizing about killing the other. Pete jokes that he would throw her in a wood chipper à la FARGO while she would slowly poison him. They drive back home at the end of their weekend and pause before getting out of their car, enjoying their moment. But it is quickly shattered by Jodi and Sadie walking out of the house with bad news: Charlotte has an ear infection and is in a lot of pain.
Debbie and Pete take Charlotte to an Eastern doctor despite Pete’s objections. The Eastern doctor tells her to keep the kids from eating dairy, gluten, or sugar. Pete mocks the doctor for his alternative suggestions since it doesn’t leave anything for the kids to have. The next day, Pete spreads his legs on the top of a table and tries to take a picture of his anus something’s happened and he is concerned. Debbie walks in on him and is disgusted but he convinces her to return the favor after witnessing her birth their daughters. Debbie looks: it’s a hemorrhoid.
At the store, Jodi continues to poison Debbie against Desi. However, Debbie appreciates Desi’s refreshing honesty and openness. Meanwhile, at work, Pete is on the phone with the realtor who tells them that a couple of Iranians are willing to overpay in this housing market but it’s still less than Pete was expecting.
Larry visits Debbie with the triplets as Debbie scrubs the house of gluten, sugar, and dairy. Sadie wants to use the computer to iChat but Debbie refuses. Sadie throws a fit and points out that Debbie is throwing out all their good food, taking away everything they like and need and that she’s being stupid. Debbie confiscates Sadie’s iPhone and all her electronics grounding her. Larry tellsDebbie that he’s got a job tomorrow and needs a baby sitter, dumping the kids on her.
That night, Debbie and Pete read through Sadie’s iChat conversations on her iPad. They realize that she’s being bullied by a boy named Joseph who was making a “Hot or Not list” and told her she wasn’t on it. Surprisingly, they find her responses to be very mature and are proud of her. Pete gets a call from work the final tallies are in from the latest record launch abysmal sales.
Ronnie suggests that they create a reunion show for the solo artist they’re promoting. He points out all the shit that Pete has wasted money on and convinces him to get the band out here for twelve thousand. Debbie meets with the accountant and realizes just how bad their financial situation is. He tells her there’s not much he can do.
At the hospital, Debbie’s gynecologist tells her the news: she’s pregnant. She says she’s thrilled, but it’s ambiguous as to whether she means it. As she drives away, she starts smiling broadly legitimately happy to be pregnant. Back at the office, Pete takes a framed photo down off his wall and goes to Larry’s house. He tells Larry that it’s worth at least 20 grand and asks Larry to sell it. Larry agrees.
Pete and Debbie help out at the school and watch Sadie from afar. Debbie asks if Pete ever wanted a bigger family but Pete says no quite quickly. Afterward, Debbie leaves and in the parking lot recognizes the kid who was bullying Sadie Joseph in the parking lot. She threatens him and makes fun of his appearance until he bursts out crying. He asks her if she’s going through menopause but Debbie flips her shit and announces she’s pregnant.
Empowered, Debbie tells Pete she is going out to get coffee with Desi to find out if she’s stealing from the store. Instead, they go to a club and flirt with some hockey players. One invites Debbie to his hotel but she turns him down appreciating the flattery of the younger man. After, Debbie confronts Desi who confesses she is an escort, which is how she affords all her nice things. She reveals that Jodi is addicted to oxy and works while high.
At Pete’s reunion concert, the turnout is shaky. Billie Joe Armstrong of Green Day shows up but doesn’t want to support the concert in the press. In addition to that, no press came. The artist stumbles over and confess that he knew his records wouldn’t sell that well they don’t anymore. But he also points out that he’s still going to be fine one of his songs will be covered on Glee. The artist goes drinking with Billie Joe and ask Pete if he’s coming but Pete turns them down. When Debbie comes home, she tries to seduce him to break the news about the pregnancy but Pete is stressed. They fight about everything including the financial states of the businesses - and Pete spends the night on the couch.
Later the girls fight and everyone ends up ganging up on Sadie, who flips her shit and storms out. Charlotte apologizes with a card and admits she was wrong. Debbie puts Charlotte to bed and asks if she wants kids but Charlotte says she’d only want one since two would just leave them fighting. The family decompresses from the argument over the next few hours the house is quiet with the sounds of silence.
The next day Pete drives the kids to school. He is approached by Joseph’s mother, Catherine (Melissa McCarthy), who tells Pete that she needs to talk to Debbie about how she screamed at Joseph. Pete doesn’t know how to respond but when pressed and hears Debbie get insulted, he tells her to back the fuck off and put Joseph on a fucking leash. He proceeds to threaten to hit Joseph with his car, rob their family blind, and pokes her in the shoulder. Catherine then begins screaming that Pete grabbed her breast.
Debbie fires Jodi for stealing from the workplace and babysitting her children while high on oxycontin. She gets a call from the principal and drives over to the school for a meeting with Catherine, Pete, and the principal to discuss the incident with Joseph. Catherine raves and rants about Pete and Debbie who pretend they didn’t do anything and makes Catherine look like a psycho. Suppressing laughter, they get away with their bad behavior and pin the whole incident on Catherine. But that night at dinner, Sadie confronts them about reading her texts and tells them both to go fuck themselves for being so insane and keeping her electronics from her. Charlotte steals back all the electronics and gives them to Sadie so she can finish watching LOST.
Later in the evening, Pete realizes that they made their kids crazy and they decide to give each other a break; they are angry at their parents, not each other. The next morning, Pete walks into Sadie’s room as she finishes LOST and all the characters are dead. She begins to have a breakdown but Pete says she can’t talk about it today; it’s the day of the party.
All the guests arrive including Larry and his family, Ronnie, Desi, and Jason - and mingle. When Ronnie and Jason both see Desi, they begin a little competition to get her attention. Desi first assumes they’re a gay couple because of Ronnie’s moustache but soon takes a liking to Jason eventually leaving with him. This leaves Ronnie completely confused as to what the fuck he’s just witnessed.
There’s a knock at the door; it’s Oliver. He gives Pete a bottle of scotch but it is still awkward with Debbie. Larry and Oliver get to talking and we learn that Oliver is a successful spinal surgeon. Larry points out that he’s never seen Debbie’s father despite the fifteen years their kids have been married. Sadie and Charlotte walk over to Debbie and ask her about Oliver and she tells them that Oliver is her father and can be their grandfather if they want him to be. Oliver goes off to play with the kids, leaving Larry to quip about how uncomfortable this scenario is getting.
Debbie prepares a toast where she expresses a desire to forgive those who wronged her family pointedly referring to Larry’s financial mooching. When it gets too much, Pete jumps in and attacks Oliver personally because he left, Debbie is a fucking untrusting psycho and he’ll never be able to live it down because Oliver abandoned her. Debbie interjects that she’d rather have her dad than Larry because Oliver doesn’t ask for anything! She doesn’t even know him. Oliver tells Pete to go fuck himself and starts to leave but stops; the rest of the guests start singing happy birthday and Oliver watches from a corner, surprising Debbie.
Debbie goes to have a smoke but the kids catch her and start to freak out. Then Barb arrives and points out that Debbie shouldn’t smoke while she’s pregnant revealing it to the kids who instantly say “they don’t want another sister.” Pete hears this and is shocked. Debbie points out that they’re stuck together forever even though Pete doesn’t want the baby. Pete says that he wants it but he didn’t want one if he could choose. Debbie tells him that’s such a nice sentiment and storms off, when Oliver stops her. He wishes her luck but tells her that it’s a much riskier pregnancy after forty. Debbie insists she’s not forty but Oliver points out that she was by telling her exactly when she was born. She’s surprised he knows that since he wasn’t there but he corrects her he drove Debbie’s mom to the hospital and saw her through the delivery.
Pete marches off on his bike to go get his anger out of his system but ends up crashing into some guy’s car ruining his bike. The guy punches him in the face and stomach for driving off. Debbie and Larry arrive as the guy drives off and bring him to the hospital, having left Oliver to look after the girls. In the hospital, Larry tells Debbie that Pete was never the fighter and that Debbie had to be the one to have punch he’ll be a pain in the ass but he’ll never leave and he’ll always love her. He apologizes for how he’s acted and promises to do better after she spots him cab fare. Debbie goes into the hospital room and makes up with Pete. They kiss and leave the hospital.
At a show, Pete and Debbie watch Ryan Adams perform and Debbie tells Pete that he should try to sign Adams. Pete tells her that Adams would probably never consider it, but Debbie tells Pete that he should try they’re going to sell the house and make memories in a new one, so why not take a chance? After all, Adams is between labels…
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