When Jon's cousin Marian tells him about her upcoming wedding, Garfield overhears and assumes that Marian will be marrying Jon, so he does everything to stop the wedding.
Jon is visited by his cousin Marian, whom he has not seen in years. Marian is happy to see her cousin again as they eat sandwiches together since Garfield and Odie not around to steal them. Marian excitedly tells Jon about her upcoming wedding before she reveals her fiancé's name is Harold John, and notes that her cousin's first name is similar to her fiancé's last name.
Garfield and Odie arrive home after getting hot dogs and sit next to the window near Jon and Marian. Garfield and Odie watch the humans before assuming that Marian is Jon's fiancé after misinterpreting "Marian John" as "marrying Jon". Jon adds to their assumptions by stating that Marian will be a beautiful bride. Odie seems happy for Jon, while Garfield is concerned.
As Garfield tries not to worry about the idea of Jon getting married, he realizes that Jon will start to pay less attention to him after getting married. Garfield then thinks about Jon and Marian having kids, worrying that he will be forced into non enjoyable games, such as "spin the bottle" (where he is put into a bottle and rolled down a hill) or "teeter totter" (where he is sprung into the air by a teeter totter and a boulder). The following morning, Jon leaves for the wedding, prompting Garfield and Odie to try stop the marriage.
As Harold and Marian are about to be wed, Garfield (dressed as a baby) and Odie barge into the chapel. Garfield claims that Jon should not marry Marian in order to take care of him; he then proceeds to devour the buffet to show how much care he needs. Jon soon stops him, informing him that he is ruining the wedding of Marian and Harold. Garfield soon finally realizes his mistake before Jon apologizes to the bride and groom, only to see that they are delighted by his cat's antics (due to Harold's sense of humor).
Jon puts Garfield and Odie outside to look after a pair of cousins from Marian's side of the family. Garfield is pleased that Jon is not marrying after all, and thus will not have to deal with kids. The young cousins arrive and fight over who will get to play with Garfield, much to his chagrin.
- Minister (voiced by Gregg Berger)
- Marian's Cousins (voiced by June Foray and Thom Huge)
- When Marian winks at Jon, her bottom eyelid is discolored.
- Toward the end, Marian has overly large eyes.