The gang's at the apartment and we see a title card that says, "eight months ago." Ted and Robin are all snuggly on the couch and SagetTed informs us that back when he and Robin were still dating, they had a joke that only the two of them out of the whole world found funny. Why not put it in a sitcom and test that theory? Barney is arguing with Marshall that March has 31 days. Marshall bellows that it doesn't and that this fact is general knowledge. "General Knowledge," Robin and Ted say in unison, both saluting. Oh man, it's gonna be one of those jokes. I can already see the marks in the soil where it's getting run into the ground. Slide-transition to MacLaren's where SagetTed says the joke continued. Lily is reading an article about corporal punishment. "Corporal Punishment," Ted and Robin salute. Oh, how they laugh. SagetTed says that something like that is really hard to stop. Back at the apartment one night, everybody's watching a movie. Marshall says he has a popcorn kernal stuck in his teeth. "Colonel Stuck-In-My-Teeth," they say. Everyone else is really sick of it. "I hate you!" Barney announces.
The present day. SagetTed says that now that they were broken up, this happened: Marshall is talking about getting a major pay raise. Instead of saluting Major Pay Raise, they just let it slide. Robin and Ted exchange a look. SagetTed says that although it seemed like they were doing well as friends, they really weren't. Being friends with your ex, he says, is hard. Welcome to the corner of Obvious and We Already Knew That, SagetTed. I bet your kids already know it, too. He says you can't be as candid as you once were. In an apartment flashback, Ted is telling Marshall and Barney about a girl in his office who was leaning over. He could see she had a pierced -- he cuts himself off as Robin and Lily are walking toward the front door. Ted awkwardly pronounces Pierce Brosnan to be his favorite Bond. Was it really worth selling out Sean Connery? Was it? Back at the bar. SagetTed says that most importantly, you can never be alone together. Barney's leaving, Marshall is going to pay and Lily is heading to pee. After an awkward moment, Ted says he's going to help pay. Robin's going to help pee.
Ba ba pa pa! (SLAP!) Sorry, just getting ready for it.
MacLaren's. Lily throws a big frozen lump on the table. "We have turkey!" she announces. So why is she dressed like a pauper from Oliver Twist? Lily's excited this will be their first big Thanksgiving together. Like on Friends? Marshall says this is going to be the best Slapsgiving ever. Barney, looking worried, says, "What?" Marshall says it's gonna be the best Thanksgiving ever. Robin says she's invited her friend Bob. You can't invite people to someone else's dinner! Rude! Lily says Robin's only been on like three dates with this guy and they haven't met him. Bob didn't have anywhere else to go. Lily is bent out of shape about it. She thinks 30 years from now, they'll look at photos and say there are the four people they love most in the world...and Bob. Robin says she's "Sore-y" and forgets how seriously Americans take their Thanksgiving. She says real Thanksgiving happened over a month ago. Barney, making fun of her "Sore-y," asks if she just called Canadian Thanksgiving the real Thanksgiving. He asks what Canadians even have to celebrate "aboat." Robin explains Canadian Thanksgiving and I still don't get it, even after years of having very close Canadian friends. As soon as I hear "Northwest Passage" I'm already dozing. Can't you Canadians just cook up a damn turkey and pretend you were founded by pilgrims? And, like, store the turkey for another month? This message brought to you by America: Yes, we are that fucking arrogant. Pass the butter. Barney asks why they're even a country. Dude, I'm sayin'! Marshall says everyone can come over early to watch the Slapsgiving Day Parade. Barney notices it again. Marshall announces that he invented a new holiday: Slapsgiving. Marshall says it's the one day of the year we all get together and (turning deadly serious) give out slaps. Barney starts to sweat.