While Barney prepares for his wedding to a mystery bride, he and Ted reminisce about Punchy's wedding, including when Marshall and Lily announced they are having a baby. Meanwhile, Robin considers telling Barney she has feelings for him.

When Marshall gets the job of his dreams, he worries that, once the company discovers videos he made in the past, they may rescind the offer. Meanwhile, Ted can't decide who to bring to the Architects Ball.

After Ted runs into an old girlfriend, he tries to make amends with her since he cheated during their relationship. Meanwhile, Marshall and Lily make a bet with Barney that could force him to wear Marshall's ducky tie.

After Robin assaults a girl who is out to ruin Barney's relationship, she is forced to begin court-mandated therapy sessions. Meanwhile, Ted gets too involved in Lily's pregnancy.

When Marshall witnesses his boss's soft approach in settling with a million dollar company, he takes matters into his own hands. Meanwhile, Ted takes his architecture class on a field trip and things don't go as planned.

When Ted goes on a date without researching the girl on the Internet, the gang interferes, showing Kevin that they are too into each other's business. Meanwhile, Lily and Marshall come to terms with finding out the sex of their baby.

The gang begins to realize their romantic partner reminds them of one of their parents. Meanwhile, Barney and Nora's planned romantic evening is ruined by a string of bad events.

Ted finally meets his mystery girl in the Slutty Pumpkin costume. Meanwhile, Barney learns he is part Canadian, and Lily has pregnancy brain.

While the gang reminisces about Hurricane Irene, Barney tries to cut a deal with Marshall and Lily to get out of wearing the Ducky Tie.

Barney and Robin find themselves in an uncomfortable situation when they hide a secret from their significant others. Meanwhile, Marshall, Lily and Ted attend a concert.

Ted and Barney discuss making a life-changing decision together, and Robin tries to discourage Marshall and Lily from moving to Long Island.

When Robin receives bad news, she decides to lie about it to the gang. Meanwhile, Marshall hangs Christmas decorations on the house in the 'burbs with help from his neighbor.

After celebrating New Year's Eve, Marshall visits his father's graveside to carry on their tradition of tailgating. Meanwhile, Barney and Ted open a bar called "Puzzles", and Robin is forced to fill in for an inebriated news anchor.

Lily and Marshall officially move to the suburbs and realize that Lily's bossy father refuses to move out of their house. Meanwhile, the gang adjusts to them moving by going to a strip club.

Lily asks for her father's help when she and Marshall decide to throw a housewarming party. Marshall's boss gets under Ted's skin and the two nearly come to blows, and Barney puts the moves on a wacky divorcée.

For Valentine's Day, Lily and Marshall invite Robin and Kevin on a weekend getaway to Vermont, where Kevin and Robin discussing taking their relationship to the next level. Meanwhile, Barney realizes he has finally met his match.

When Robin breaks up with Kevin, Ted confesses his feelings to her. Meanwhile, Barney is on a mission to find something private of Marshall and Lily's.

Barney continues his pursuit of Quinn. Ted has to deal with Robin's old room, while Robin gets a taste of suburban life from Marshall and Lily.

The gang tries to break up Barney and Quinn after learning they plan on moving in together, leaving Robin and Ted to fight over who deserves to sublet her apartment.

Ted, Marshall and Barney embark on another "trilogy time", where they get together every three years to watch the "Star Wars" trilogy and envision what their lives will be like in another three years. Meanwhile Barney and Quinn move in together.

Although Ted is happy with living alone at his new apartment, Barney tries to convince him about going out every night. Lily has a naughty dream about someone other than Marshall. Robin finally starts her stint as a news anchor at World Wide News.

Marshall panics when a baby shower indicates that the birth is close at hand and accidentally takes a road trip with Barney. Ted hallucinates seeing Robin while trying to get over her and decides to patch up their differences. Barney tries to talk Quinn out of being a stripper.

While Marshall is in Atlantic City with Barney, Lily goes into labor, leaving him desperate to make it back to New York before the baby is born. Meanwhile, Ted and Robin try to distract Lily during her painful contractions.

Ted is conflicted when Victoria approaches him on her wedding day and asks him to elope. Meanwhile, Barney and Quinn are arrested by airport security while on the way to Hawaii when Barney refuses to open a box they are travelling with.