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

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.

When Robin learns that Barney never asked her father’s permission before proposing, she insists that he seek his approval before announcing their engagement. Meanwhile, Ted keeps his feelings concealed by throwing himself into planning their wedding.

Robin desperately tries to locate the item that she buried in Central Park years earlier to wear as her "Something Old" for the wedding. Meanwhile, Marshall and Lily ask Ted to help them pack for Italy, and Barney invites Robin's father to play Laser Tag in order to bond with him.

The gang must figure out how to make the Stinson Hangover Fixer Elixir to help Barney recover on the day of the wedding.

With only a half an hour left before the wedding, Robin and Barney panic; Lily and Marshall rewrite their wedding vows.