प्लॉट

Barney tells Ted that single women like architects. But will Ted use this useful tidbit of information to cheat on Robin after they have their first fight?

Ted and Robin have just had their first fight. Part of the issue is that Robin believes that Ted's job is boring, and about which he rambles on and on, especially when he's had a bad day. Barney convinces Ted that his job may or may not be boring, but that he needs to be more convincing and suave in saying what he does for it to be attractive to the women. For fun, Ted tries using his job as a pick-up line to a beautiful woman - a kick-boxer named Anna - and it works. Robin hears about Ted picking up this woman, but she isn't overly concerned about what it means. But as Robin, with Lily by her side, goes on trek following Ted's movements that night, Robin becomes more concerned as it looks as if Ted is willing to go outside of his comfort zone to impress and thus sleep with Anna. Robin comes to a realization about herself as the night comes to a close.—Huggo

After having their first fight as a couple, Ted meets Marshall and Barney at MacLaren's while Robin meets Lily in a nail salon. At work that day, Ted's boss unveiled a design for a skyscraper which is remarkably phallic (78 floors tall pink marble tower with a rounded top and 2 spherical entryways at the front. This is a huge project and if the firm doesn't get the contract it could go under), but when he tried to tell Robin about it, she said that she didn't want to hear about his job because his work stories are uninteresting compared to hers. She even goes on to say that she doesn't like Field of Dreams (she calls the movie stupid, and it is on the all time best movies list for the guys). Lily explains to Robin that even if she is not interested in Ted's work, listening is still an important part in a relationship. Robin believes that Ted is mad because of her comments about the film and not about his job (in fact, he is very upset about both things).

Marshall asks Ted to join him at a law school party, but Ted has to return to work. Barney tells him that his job isn't boring: women think that architects are hot, and Ted just needs to present his career with the right attitude. As the three leave for their evening plans, Ted approaches a woman at the bar and asks her what she thinks about architects. She tells them that she thinks that architects are sexy, and they begin chatting.

Robin heads to MacLaren's with Lily to apologize to Ted, but he isn't at the bar. Robin asks the bartender about Ted, and a woman at the bar tells her that he left with her friend Anna (Dawn Olivieri) to go Marshall's law school party. Robin is calm, happy that Ted found someone to talk to about architecture so that she doesn't have to hear it. Lily can't believe that Robin isn't jealous that Ted is hitting on other women. Robin says that she is picturing the other woman as unattractive, but when her friend says that she is a kickboxing instructor and looks great, Robin decides to go to the party to check on Ted.

Lily and Robin go to the law school party and ask around for Ted. The party's host, Brad (Joe Manganiello), speaks reverently of Ted Mosby the Architect, but says that he left with his date and Marshall to go dancing at a techno club, Posers. Upset that Ted, who hates clubs, would go dancing with another woman, Robin tries to call him to apologize. When Ted doesn't answer his phone, Robin calls Marshall, who tells her that Ted is at work. Shocked that Marshall lied to her, Robin realizes that Ted is cheating on her.

At the club, the bouncer (who also refers to "Ted Mosby the Architect") tells them that Ted left with his date to go to her apartment across the street. After a bribe of her clutch purse, the bouncer tells Robin where Ted's date lives, and the girls go to the apartment. Finding the door unlocked, they sneak in and discover Barney in the woman's bed. Robin asks where Ted is and Barney replies that Ted is at work. Barney then tells them that he has been pretending to be Ted all night, introducing himself as "Ted Mosby: Architect" to the woman at MacLaren's after Ted left.

Lily reassures Robin that everything is fine because Ted isn't cheating on her, but Robin says that she hates how crazy and paranoid she has been acting. Lily tells her that people act crazy and paranoid in relationships, and she really misses those feelings. Leaving his standard goodbye letter for the woman he just slept with, Barney, Robin and Lily flee. Robin brings donuts and coffee to Ted at work, apologizes for their fight, and tells him that she wants to be the person to whom he complains about work. Ted shows her an alternate design for the skyscraper that he has been working on, and Future Ted tells his kids that it was the first time he'd ever shown his drawings to someone; what's more, the skyscraper ended up being built and he had pointed it out to them when they had previously visited Spokane as a family.

The woman Barney slept with finds his goodbye letter on the bed, wherein Barney pretended to be a ghost who could only spend a day on Earth every 10 years, and "chose to spend it with [her]." However, he slips up as he signs the letter "Barney" (when she thought he was Ted Mosby), leaving the girl utterly confused.