At a bachelor party Travis (Dan Gauthier) hosts for Crawl (Pauly Shore), he and Theo (Dennis Burkley) drug his and Rebecca's friend Tracy's (Tiffani-Amber Thiessen) drinks and place them in the barn to make it look like they had sex, which would give Rebecca the right to break off her engagement to Crawl (even though the two have fallen for each other for real during their time at her family's house) and in turn give Travis a guilt-free reason to split with Tracy and propose marriage to Rebecca again. Theo participated due to not liking Crawl since day one.
As Crawl is attempting to hitchhike back to Los Angeles, Tracy finds him and informs him that she figured out Theo and Travis were behind their being put in the barn like that, due to discovering a drug bottle in her car that they used and the driver's seat being pushed back to a distance that would only accommodate someone of Theo's girth. They return to Rebecca's family's house at Thanksgiving dinner right before Rebecca can answer Travis' marriage proposal. After presenting the evidence Theo confesses to his and Travis' wrongdoings. A disgusted Rebecca tells Travis to leave, Crawl nailing him with a few choice punches before he does, and Rebecca's father fires Theo from his job. Tracy is asked to join them for Thanksgiving, which she does.
Rebecca's parents ask about her and Crawl's engagement, and though she almost tells them it was all a hoax, Crawl covers for her by saying that they're gonna give this engagement some time and not rush into getting married, which Rebecca's parents are cool with.
The last scene shows Crawl, Rebecca, and her family taking a picture together.