My tolerance for this show is about zero of late, and when you combine that with the migraine I've been fighting all day, we're starting out at a negative 30 here. I'd like to say that I was pleasantly surprised and we ended up back at zero, but I'd be totally lying. The stupid intro about Barney's magically disappearing bed for whores (which might have been cute in Season 1 or 2) and his and Robin's discussion of adoption as a crossword clue instead of as a viable option (it's not like they're two actual fully formed grown-ups who are about to get married or anything) started the episode off on the wrong foot for me, and it really never recovered.
In the main story, as Robin and Barney's wedding date nears closer, they have to figure out where they are going to live. As almost-newlyweds, Robin wants to make a happy home for the two of them that isn't full of reminders of the hundreds of women her future husband has banged in the past, but he is reluctant to give up his beloved bachelor pad. It's like someone watched Barefoot in the Park and decided to make a grosser, crappier version of it, where Robin is the stuffy one and Barney is happy to live somewhere nearly inhabitable for most actual human beings because he's with the person he loves.
Barney hides in his closet and does the whole floating Oz head as he offers his fortress of Barnitude to Ted, hoping to keep the bang palace in the family… or something like that. The floating head bit was mildly amusing… briefly. And Barney compares his place to Superman's fortress of solitude (hence, "The Fortress" title of the episode), but I don't remember Superman bringing hundreds of women to the Fortress so that he could have sex with them and/or trick them with a green screen into thinking that they were in Paris or that the world had ended. Maybe that was in the comics?
Ted turns him down… which is confusing, because where exactly is Ted living at this point? Didn't his apartment get destroyed by Abby Elliott? And even if Barney's place would need major disinfecting, it does at least look pretty nice and would be better than being homeless. Anyway, Robin is annoyed, sets up an open house (which is not the orgy Barney was hoping for) and tries to get people to buy it while Barney tries to sabotage the sale by showing off the apartment's unique features, like an escape chute from the kitchen (which sadly leads to an alley and not a rollercoaster of death like Nothing But Trouble), or fire sprinklers that go off when a lady starts talking commitment. Someone must have an in with the building management and the city permit department, because adding a wall in a bedroom in New York is a rigmarole, so we can't even imagine the logistical nightmare of an escape chute (with or without the dummy testing).
Eventually Robin finds a buyer: a couple who are interested in the place for its massive square footage and plan to gut it. Knowing what's gone on in this apartment, short of calling in the CDC, that's probably the wisest decision. But Robin gets sentimental and realizes that the apartment is just so Barney and she can't see it destroyed, so they decide to stay come up with some other uses for the apartment's never-before-seen features.
In the other stories, Lily's super busy with her job finding art from The Captain. The Captain has become Stefan from SNL, dispatching her with weirder and weirder requests. Lily ignores her husband (and baby Marvin) and at some point dresses like Edna Mode from The Incredibles, except that she's obsessed with wearing an ugly cape instead of ridding the superhero world of them.
While she's off finding mole people, Marshall is getting increasingly upset about being left alone. This mostly surfaces in the fact that he can't watch this show's crappy knockoff of Downton Abbey because he promised he'd wait for her. Ted constantly tempts him to watch the goings on of Woodworthy Manor and eventually he caves, and when he gets mad at Lily for cancelling on them yet again, he does the unthinkable and tells her a spoiler. Heaven forbid.
There's also an insipid plotline where Ted and Marshall pose as a couple at the open house (mostly to get under Lily's skin) and then Ted does a terrible British accent and finds a woman who wants to be his first straight sex. It's as awful as it sounds.