It turns out Robin, still a Canadian citizen, may be getting deported back to Canada when the guy from a bar fight she got into is pressing charges. Turns out there's a citizens test offered tomorrow and Barney is not willing to let his girlfriend get shipped back to Canada without a fight. While Robin is already prepped on the actual facts for the exam (Presidents, Bill of Rights, etc), Barney decides to focus on taking the Canadian out of her and making her act American by teaching her such important things as forgetting about the Queen and learning Jim Varney, the comic genius responsible for the Ernest series.
After completing her training, Robin stops for one last beer at her Canadian bar, Hoser's, and ends up on a Canadian bender that ends up with her going to a Brian Adams concert and passing out in a hotel in Toronto. Barney "flies across the Atlantic" to rescue her and she initially doesn't want to come back. He takes her for some coffee at a Tim Horton's where the cashier calls her American. To put Robin in a better mood, Barney gives a negative speech about Canadian and gets his butt whooped. After some free hospital care, Robin takes Barney back to America and decides she's a little Canadian and a little American...dual citizenship time!
Meanwhile, Ted and Marshall get word that their favorite, disgusting pizza place, Gazola's in Chicago is shutting down. They apparently used to road trip there all the time in college and decide to do it one last time. Ted is really looking forward to some alone time with Marshall, but is shocked to see he invited Lily. No problem, they hey load up on cans of Tantrum, their classic road tripping energy drink and start.. until they have to stop in the first five minutes for Lily to pee.
It gets worse when Marshall pulls over to stay in a bed and breakfast for the night. While there, and maybe it's just the Tantrum messing with his head, Ted sees Marshall and Lily morph into a singlular blob. Ted tricks Marshall into thinking they're going out for beers and kidnaps him in his robe and all and they head to Chicago, leaving Lily behind. They get there, have the awful pizza, but Marshall feels so guilty, still unable to reach Lily by phone, he wants to head back mid-slice. They get back to find out Lily was so comotose from all her spa treatments she didn't even realize the boys left her.