In a flashback to 2004, Chris and Reagan stand at the altar in a cowboy-themed Vegas wedding chapel, preparing to be married. Just as they're about to deliver their vows, Chris has second thoughts. It's not that he doesn't want to marry Reagan, he just doesn't want it to happen like this. After some convincing, Reagan begins to agree with him, and they decide to have an actual, legitimate wedding.
Six months later, Chris and Reagan's wedding rehearsal dinner is in full swing. Quirky family members abound, including Uncle D, Chris' creepy uncle who likes to hug too much, Reagan's parents, who disapprove of Chris, and Chris' parents, who suspect that Reagan is a floozy. Reagan worries that the craziness of the wedding will distract from their marriage, but Chris convinces her to go ahead with it.
Later, Chris delivers a heartfelt speech declaring his love for Reagan. Her parents still aren't convinced. Reagan is about to give a speech when Ava and Walt interrupt the party to announce that Ava has been given her own television show. The announcement distracts from Reagan's speech. It's already happening: she's being overshadowed by her own wedding.
Chris' parents try to encourage him to uphold the Brinkley family tradition by wearing a kilt for the wedding, but Chris isn't into the idea. Nonetheless, his parents are relentless. Meanwhile, Reagan goes to Ava for some encouragement, but Ava is too distracted by the news of her show. Scott is at the dinner, but he spends all of his time making out with his new girlfriend, Connie.
Ava surprises Reagan by asking her to be the executive producer for her new show, which is great news. Scott and Connie immediately announce that Connie is pregnant, and they'll be living together, just like Chris and Reagan. This is news to Chris' parents, who don't approve. Chris' mother is finally justified in calling Reagan a "floozy." So far, this wedding is proving to be very frustrating.
On the day of the wedding, Chris' parents guilt him into wearing a kilt for the ceremony. Reagan is forced to solve everyone else's problems while she's getting her hair and makeup done. Connie is focused on her pregnancy, and Ava is focused on her show. So far, Reagan's wedding day is about everyone except Reagan.
At long last, Chris and Reagan's wedding ceremony begins. Before Regan can even walk down the aisle, Scott proposes to Connie on the altar. She accepts his proposal; the crowd cheers, and Reagan storms off, fuming. Chris tries to console his bride-to-be, and eventually he convinces Reagan to join him at the altar. Chris decides to wing it on the vows, and his heartfelt, sentimental speech finally puts Reagan at ease.
At the wedding reception, Ava tries to deliver a tear-jerking speech, but Walt won't let her get a word in edgewise. Ava tells Reagan that her first task as executive producer of The Ava Show is to get rid of Walt. Chris steals his new bride away to the coat closet, where he's arranged for the two newlyweds to share a dance to their favorite song while wearing the cheesy cowboy hats they wore in the Vegas wedding chapel.