時間來到 2030 年，泰德告訴孩子自己如何認識他們的媽媽，故事從 2005 年馬歇與莉莉訂婚開展。

泰德舉辦派對，冀望能再次見到羅繽，可是她卻沒出現。於是，泰德辦了一次又一次的派對。

巴尼計畫在機場和女孩們見面，但是因為他和泰德被保全逮到而失敗了；另一方面，莉莉對羅繽感到忌妒。

泰德與一位舊情人再次搭上線，很快就想起自己當初離開她的原因。巴尼付錢給羅繽，要她在轉播時講出難聽的話。

萬聖節狂歡在進行中，而泰德如同往年參加一場無趣的派對，尋找多年前在那裡遇到的女孩。

泰德登記相親服務，接著他明白愛情並非科學。馬歇和莉莉在公寓中面對恐怖生物。

As Lily becomes more of a permanent fixture in the apartment, Ted feels like he is being edged out of the mix by his engaged roomies. Petrified of being left alone and homeless, Ted tells Marshall that when he and Lily are married, he wants the apartment. The problem is that Marshall wants to keep the place too, so they settle it like real "grown-ups" -- launching into a sword fight that leaves one man down for the count.

Ted and Robin are surprised to run into Barney when they volunteer at a homeless shelter on Thanksgiving. Lily is on the brink of freaking out when she goes to Thanksgiving dinner at her future in-laws house.

After being forced into knocking back 5 shots, so he will stop thinking, Ted goes on a partying rampage. The next morning he wakes up with a woman in his bed, but he does not know who it is. So he turns to his friends to try and piece the night together and work out who the woman is in his bed.

Ted rents a limo to take the gang out to sample five New Year's Eve parties in a quest to find the perfect celebration.

Robin accepts Ted's invite to a friend's wedding, but thanks to Ted, the couple may never make it down the aisle.

Ted finds a new woman at the wedding. They want to remember the evening so they don't exchange last names or numbers; but Ted takes a big fall when he tries to find out her name.

After agreeing to take things slowly and not have sex for a month, Ted and Victoria decide that they have waited long enough.

A mysterious tape arrives for Barney from one of his numerous ex-girlfriends, and the entire gang watches it. But, in order for them all to find out how she broke Barney's heart and made him into a suit-wearing bachelor, everyone must share their most embarrassing moment.

Things are going great with Ted and Victoria's relationship, but when Victoria is offered her dream job, the couple have to make serious relationship decisions. Meanwhile Marshall and Lily set out to purchase their wedding outfits and find out that none can afford what they bought.

Marshall interns at the corporation where Barney works and Lily finds that he is becoming a shallow jerk as he tries to fit in with his crude fratty coworkers. Meanwhile, Ted feels guilty when he receives several gifts from Victoria (Erika Singh) while he hasn't sent her anything.

Robin, who is very lonely, asks Ted to come over to her apartment after 2 A.M., but he isn't sure if he wants to go as he has a phone call on the way over with his friends, and with Victoria on his mind

Robin is nominated to receive an award for a news report and everyone needs a date to take to the show. Barney introduces Ted to Mary as a date that Ted can take to the show. Originally Ted is opposed to the idea of just trying to save face in front of Robin but when she shows up with a date he changes his mind. Robin asks Mary lots of questions, and Ted begins to really like Mary, despite her occupation.

Lily, Barney and Robin attend a high school prom to scout out a potential band for Lily and Marshall's wedding reception. In order to get in Lily and Robin pretend to be the dates of two kids who were going alone. Ted and Marshall are back at the apartment where they are preparing the invitations to be sent out.

When a matchmaking company calls Ted claiming they have found his soul mate, he is forced to postpone his date when Lily asks for his help.

Ted tries to keep Robin from going on a camping trip so that she can spend time with him. Barney enlists the help of an old flame to perform a rain dance. At the same time Marshall finds out about Lily's interview for the fellowship in San Francisco.