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.

When Barney learns Ted has a list of things he thinks the gang is too old to do, he sets out to do every task within 24 hours in order to prove Ted wrong.

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

When Ted and Barney argue about who has "dibs" on a hot girl, Ted realizes that she is there with Cindy, a girl he previously dated who is also the roommate of his future wife. Meanwhile, Robin is heartbroken over Don, and Marshall can't keep quiet about his desire to start a family.

Marshall and Lily try to figure out how to conceive a baby with the gender of their choice; Robin's perky new co-anchor irritates her.

Afraid they will never get pregnant, Lily and Marshall decide to see a specialist. Robin begins her new job.

While on a trip to Minnesota, Ted and Barney try anything to make Marshall laugh. Marshall runs into an old nemesis from high school.

Barney declares February 13th a holiday for desperate women. Marshall receives a Valentine's Day surprise from Lily. Zoey and Ted work on figuring out their relationship.

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.

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.

When Barney designs an extensive pre-nup, the guys take note and propose their own relationship amendments to their significant others. Meanwhile, Quinn is outraged and draws up a pre-nup of her own, which causes friction between the sexes.

Robin and Ted reminisce about past relationships as they search for a drunken Barney on the day of the wedding; Lily and Marshall come to a resolution; Barney befriends two men who are eager to meet women.