The title card tells us that it is 11 AM on a Friday and just 55 hours before the wedding, which means in my half-assed math that the wedding will be Sunday at 6 PM? That's stupid. I hate Sunday evening weddings. You have to take Monday off from work and it's really inconvenient for everyone involved, but I guess I'd expect nothing but selfishness from Barney and Robin at this point.
Lily and Ted are in a car driving out to Farhampton, and Ted's sporting his driving gloves and rattling off ridiculous facts about Long Island. He also keeps stopping at hole-in-the-wall places with butter churning and that sort of nonsense. Lily gets so disgusted that she starts banging her head into the side of the car (kind of like I am with my coffee table at having to watch this show still) and begs him to let her off at the train station.
On the train she starts muttering about the passive aggressive pictures that Marshall's mom keeps posting about baby Marvin, and upon hearing the words "unicorn" and "lonely", The Mother interrupts her and asks her if she wants a cookie. Specifically, it was a Sumbitch cookie, which is filled with chocolate and peanut butter and caramel. (I feel like someone at CBS needs to send a batch of those to me, stat).
The two become fast friends, as Lily regales The Mother with the tale of how her friend Ted pissed her off. We even learn that The Mother loves driving gloves and stupid roadside attractions, but doesn't like slow driving and in the future gives Ted the nickname "Lady Tedwina Slowsby." At some point The Mother realizes that Ted was trying to get rid of Lily, and Lily thinks it has to do with The locket. You know, the one they were digging in Central Park for last season that I had hoped we were done with? That one.
So Lily hightails it to the wedding and tackles Ted before he can give a box to Robin, but it turns out that the box contains nothing more than a picture frame of the gang all together eight years prior. But we see that Ted days before did go to great lengths, even flying to LA to go through Stella's storage units (please tell me we get a Storage Wars cameo out of this at some point) to find the missing locket. Ted may turn out to be the big wildcard that Robin and Barney were worried about.
The soon-to-be newlyweds are in a town car (being driven by Ranjeet, of course) and having a bit of a panic about the fact that their wedding could be ruined by any number of relatives, including maybe a ring bear (yes, bear) and a woman on a moose. At some point in the conversation they realize that they share a cousin Mitch. (Remember when we learned that Barney was a little bit Canadian a long time back?). They both get awkward and decide that being related is OK since they aren't having children and Barney tries the King-Joffrey-turned-out-fine argument. But they finally get through to a family member who tells them that the cousin was adopted and there's like seven layers between them, and no blood, so they can get married without the ickiness.
Marshall has the stupidest storyline. He's on a plane back from Minnesota and his mother posts a picture on Facebook (or whatever knockoff this show uses) and it is announcing that he's going to be a judge, and Marshall hasn't had the "Italy or Judge" conversation with his wife yet. So he spends a lot of time annoying Sherri Shepherd, and trying to get his mother to stop looking at porn so she can take down the picture before Lily sees it. He gets thrown off the plane, as does Sherri Shepherd, and they find out there's only one seat on the last flight of the night (why they couldn't take one Saturday morning since he's clearly got time beats me, but whatever). The two start racing across the airport, so we've got that to look forward to.