Cory and Topanga's wedding day has finally come. There is some unexpected tension between Cory and Shawn when he storms into the girl's apartment and expresses his anger about how Cory is ignoring his feelings. Shawn is late coming to the Matthews where everyone is waiting, and Cory begins to worry. Shawn shows up without the tuxedos and hasn't done any of the things that Cory asked him to do. The two get into an argument and Shawn tries to tell him that he needs to talk about what he is feeling on this important day, but Cory doesn't want to hear it. When Cory questions the competence of his best man, Shawn quits and says he wants no part in his wedding.
Eric is thrilled that he now gets to be the best man, so he hurries out the door to complete the tasks that Shawn failed to finish. A few hours later, Eric not only brings everyone's tuxedos, but also shows up with a limo. Eric also changed the location of the wedding from the Matthews living room to the ballroom of the fancy Philadelphia Victorian Hotel. The wedding guests are impressed by the location but confused as to why everyone is referring to Topanga and Cory as the Petersons.
Nonetheless, the wedding ceremony begins and all Cory can think about is that Shawn isn't there. Eric realizes that he forgot the rings when the ring bearer walks down the aisle without them. However, he is bailed out when Shawn shows up with them, and hands the rings to Cory. Shawn's comments spark another argument in which they call each other harsh names. Shawn reveals that he is just worried that today is the last day they will be best friends and things will never be the same. However, Shawn is supportive of Cory and Topanga's marriage and gives them his blessing. The ceremony continues as Cory and Topanga recite their vows and kiss each other.
Shawn proposes a toast to Cory's happiness and Topanga's new best friend. Eric presents them with one final gift—a key to the hotel's finest suite, which the two don't hesitate to dart off to. The wedding winds down in a hurry when Mr. Peterman shows up and demands an explanation. On Eric's prompt—a loud whistle and the words "run like hell"—the guests scramble.