Doug and Carrie face problems when they try to decide where to go on vacation.

Doug, Carrie and Arthur head out to the airport to visit with Doug's parents while they have a short layover at Kennedy Airport on their way to Montreal. While there, his parents ask him to sign their living will, making him the one responsible for pulling the plug. When his sister Stephanie gets wind of this, she is offended that she wasn't the one asked to be responsible.

While cleaning out the Heffernan freezer, Carrie comes across the top tier of her and Doug's wedding cake, and reflects back to the time when they got married. As she takes a trip down memory lane, Carrie remembers her uneasiness prior to their wedding day and her desperation in needing a sign from God to be sure about the marriage. The priest calms Carrie's insecurity by informing her that she and Doug actually met years before when they were kids. Carrie feels that that's a "sign" from above, but Doug later learns that it was Danny, his cousin, whom she met, not him, and is afraid to tell her the truth. Also, Arthur convinces Doug's parents to cover the cost of the wedding, and then proceeds to spend all their money to make the day extra special.

Doug starts to dream more seriously about running his own sandwich shop now that his Uncle Stu has generously offered him a large sum of money to see him realize his dream. However, Carrie has major reservations about this, knowing that Doug's gifts are not in running a business. Not to mention that Danny, Stu's son, is very jealous and angry that his own father would back Doug's business venture, but not his own.

The fourth season concludes with Arthur visiting a psychiatrist and recalling via flashback a disturbing encounter with his dad that may explain Arthur's abrasive personality.

A toy from their childhood leads to a rift between Deacon and Doug. Meanwhile, Carrie tries to give her father a great Christmas gift, but this proves hard to do when everyone thinks of the wrong gifts they are receiving, altering their original gift choices.

Carrie learns from Janet that Doug had a dog when he was 11, that they still have today, and Doug is 38! Janet admits to Carrie that the dog died, and they replaced it without Doug knowing.