正当泰德开始了他的新事业，将要遇上他的真命天女时，莉莉强迫巴尼和罗宾展开一场谈话，确定他们的关系。

泰德与他七年前同一个相亲对象相了亲，巴尼和马修发现了一个跟莉莉长得一模一样的脱衣舞女。

当莉莉和马歇尔意识到罗宾和巴尼是完美的双人约会朋友时，他们太努力地给人留下深刻印象，表现得太强了。

当巴尼试图说服罗宾成为美国公民时，特德和马歇尔的传奇之旅在马歇尔邀请莉莉时发生了错误。

尽管巴尼竭尽全力想成为一对完美的夫妻，但他的无所不知态度让他和罗宾陷入了麻烦，他们不得不向马歇尔和莉莉寻求关系建议。

在巴尼和罗宾的关系遭遇坎坷之后，莉莉想出了一个完美的分手计划，向罗宾的著名朋友艾伦·锡克求助。

与罗宾的恋情结束后，巴尼翻出了他的 "约炮宝典"，帮助自己重返约会现场

Barney freaks out when Marshall bequeaths a "slap bet" slap to Ted and Robin. Meanwhile, Lily's estranged father shows up for Thanksgiving.

When a perfect girl finally shows up, the gang tries everything to help Ted, while Marshall takes action when he discovers a letter written by younger himself.

When Marshall picks up smoking again, it prompts Lily, Ted and Barney, ex-smokers all, to succumb as well. Meanwhile, Robin gets a new co-anchor at her show...

When Barney debates giving up wearing suits in order to land a hot bartender, his conflicted feelings lead to an amazingly awesome musical number. Meanwhile, Ted gets one step closer to meeting the future mother of his kids.

When Lily refuses to believe that Jenkins, Marshall's attractive female colleague, kissed him, Marshall insists Jenkins tell Lily what really happened. Meanwhile, Robin finds out that a drinking game has been made up about her.

When Barney is about to complete the perfect week - landing seven different girls in seven days - the gang roots him on in order to forget about their own miserable week.

When Lily and Marshall forget to fix up Ted on a blind date for Valentine's Day, they use one of Barney's many discarded girls to see if they may become Ted's future wife. Meanwhile, Robin's obnoxious colleague invites her to a party at his apartment

When the gang tries to convince Ted that he is being strung along by Tiffany, they reflect about relationships where each of them has been in the same situation.

When Robin confesses that she is still angry with Barney for the way he handled their break-up, she enlists the help of Anita, a self-help author who plans to beat Barney at his own game.

When Ted ruins Lily's birthday dinner celebration by bringing a date, Lily goes to great lengths to keep her out of the traditional photo she takes every year of the gang.

When Marshall gets mugged, Lily decides she wants to get a gun for protection, so Marshall comes up with a convoluted story about the mugging to deter Lily from following through.

When Ted attends his mother's wedding, he is extremely disturbed by her overly affectionate relationship with her fiancé, which forces him to think about his own life and make an impulsive decision.

When Ted and Barney jeopardize Robin's new relationship by professing their love for her, Robin realizes that she is finally over them. Meanwhile, after spending a weekend sleeping in twin beds, Marshall and Lily decide to get twin beds at home.

When Ted, Marshall, Lily and Barney crash a highfalutin party at a swanky New York apartment, Ted gets the chance to mingle with the snooty guests and show off his intellectual side.

When Ted takes a date to see a new hit movie, "The Wedding Bride," he is shocked to learn the story is loosely based on his life, and that it was written by Tony, the man Stella left him for at the altar.

Marshall and Lily make a secret pact to start trying to have a baby if they ever finally see Barney's doppelganger. Meanwhile, Robin finally gets an offer for her dream job.