When a matchmaker with a 100% success rate turns Ted away because he is not compatible with any of the available women in her database, he is still determined that he is going to find his match. After getting information from the matchmaker’s computer, Ted pays a visit to a very cute but taken dermatologist in an effort to prove the prediction wrong that there are no women out there for him. Meanwhile, Marshall and Lily are obsessed with ridding their apartment of a critter.
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.
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.
Marshall is all set to celebrate his beloved Fiero hitting the 200,000 mile mark but it stops. While the gang sits in the mechanic's garage and waits to hear what will happen to the vehicle they think about times gone by that they have spent together in the car. We also get the story of how Ted met Marshall.
After sharing a kiss at the beginning of the summer, Robin and Barney are unsure how to handle their mutual attraction. After some consideration they tell the gang they have decided to remain just friends, but secretly continue seeing each other. They are able to get away with their secret romance for a couple months, but are discovered when Ted, Marshall and Lily walk in on them together. They explain to the gang that they are happy with their casual relationship, and didn’t want to complicate it by defining it. This is unacceptable to Lily, who pressures them to label their situation, and ultimately locks them in Robin’s room to force them to address it. Meanwhile, Ted is anxious about his first days as a professor at Columbia, which is made worse when he shows up at the wrong class and starts his lecture.
Barney takes Marshall, and Robin to a strip club where they find a stripper who looks almost exactly like Lily. Meanwhile, Ted discovers he had been fixed up with the same woman, Jen seven years earlier.
Marshall and Lily want to hook up with Barney and Robin for double-dating and fun, but their desperate eagerness to please is a huge turn-off. Meanwhile, when a succession of girls come to his apartment and immediately fall asleep, Ted is bummed to learn he is a "Sexless Innkeeper" whose "dates" are only interested in a comfy place to crash
When Lily goes into labor, Ted and Robin distract her by telling her stories while Marshall hurries back from Atlantic City. 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 traveling with.
Robin takes steps to have Patrice fired from WWN, while Marshall puts a jinx on Barney. Later, Ted invites his architecture professor to the dedication of the GNB building, and Marshall and Lily bump into an oddball acquaintance from college. Christmas approaches and Ted wrestles with whether to tell Robin about Barney's intentions involving Patrice, while Marshall and Lily get an early Yule gift, a night away from Marvin, but a case of separation anxiety strikes and threatens to ruin the evening.