The episode begins and the summer of 2012 is "The Summer of Love", Barney and Quinn, Ted and Victoria, Robin and Nick, and Marshall, Lily and Marvin everyone are as happy as can be; which means, there are absolutely no good stories, as is revealed. So the show skips ahead to October 2012, which kicks off as what came to be known as "The Autumn of Breakups". Barney's boss gives him advice on getting a pre-nup because he lost everything to his ex-wife in the divorce settlement, and therefore doesn’t want the same happening to Barney. She even got one of his kidneys, his boss reveals to Barney. Barney is visibly worried on hearing this.
Later, Barney hands Quinn a massive stack of papers, much to her surprise. He then clarifies to her that it’s their pre-nup. Quinn though doesn’t take too kindly to it, and is annoyed that he wants her to sign it. Barney's on his part is annoyed that she wants to read it first. One section reads that in the event of a divorce, Barney would retain weekly visitation rights with Anne, Sarah and Molly. She thinks it's sweet that he named their future kids, but Barney's boss reveals those are Barney's names for Quinn's "lady parts". "It's important for the girls to maintain a relationship with their daddy," Barney tells her, elaborating further.
In addition to rules for their divorce, there are "suggestions" for how she must conduct herself during their relationship. This includes regular weigh-ins, regular breast enhancements, regular hair removal and more. It also notes that Quinn's parents are allowed to stay at their house provided they arrive in an urn. Quinn is visibly outraged at the suggestions. Later, Barney reports back to the guys, who agree that the pre-nup is crazy. Nick even shows up and says he can imagine it's crazy. But that night, Ted and Marshall and Nick each talk to Victoria, Lily and Robin about how it kind of makes sense to occasionally revisit the terms of their relationships.
Then, just like that, one of those couples would break up the very next day. Old Ted admits it wasn't Lily and Marshall. But one of the remaining couples would break up the very next day. The next day, Robin and Lily get to the bar and tell Quinn about how Nick and Marshall were saying it made sense to revisit the terms of "blah, blah, blah" Marshall had told Lily she's "too precious" with the baby. Lily recalls when they got home from the hospital and Marshall tosses the baby in the air. Lily freaked out. Nick, on the other hand was bothered that Robin watches TV when they're making out. Robin then admits that she might be a little weird, because she was actually watching herself on TV.
Victoria shows up and recounts something Ted did the night before. He let Klaus, Victoria's ex, stay with them for a while playing the hero, but then regretting it later. Klaus walked around naked and his ferret had a bunch of babies. Quinn on hearing all of it has an idea. She is next shown telling Barney that, she's on board with the whole pre-nup thing. Turns out, she's made her own pre-nup with the help of Robin, Lily and Victoria, so it won’t be a one-way thing after all. Quinn's pre-nup calls for her to take custody of Barney's suits. He's also allowed to attend any function at the Playboy Mansion provided he shows up in an urn. The guys show up, too, and a showdown of pre-nup provisions ensues.
Barney's boss finally speaks up and encourages everyone to remember that love is, trusting someone enough to tell them what's really bothering them. They all do, and everything is fine for a while. That night, the Autumn of Breakups claims its first victims. It isn't Robin and Nick, or Ted and Victoria. But, Quinn and Barney add even more stacks to their pre-nup and realize it shouldn't be that complicated. Neither of them trusts the other, so they call an end to it.
Barney tells Marshall and Ted he's alright with it. Then, a little ways down the road, Barney is shown talking about how legendary his wedding is going to be. His boss asks if he needs a pre-nup and Barney says, "Not this time". Robin then comes in and she and Barney leave for lunch, kissing on the way out the door. The episode ends at this point.