Kirk Kettner (JAY BARUCHEL) is a young TSA employee who lives in Pittsburg, doesn't have a lot of self-esteem, and is still fixated on his ex-girlfriend, Marnie (LINDSAY SLOANE), despite them breaking up several years ago. Of course, it doesn't help that she still hangs out with his parents, Barb (DEBRA JO RUPP) and Walt (ADAM LeFEVRE), older brother Dylan (KYLE BORNHEIMER) and his condescending, pregnant girlfriend, Debbie (JESSICA ST. CLAIR), always with her boyfriend, Ron (HAYES MacARTHUR), in tow.
Kirk still wants to get back together with Marnie, something that doesn't sit well with his friends and coworkers, Stainer (T.J. MILLER), Jack (MIKE VOGEL) and Devon (NATE TORRENCE), who think he should move on. He gets that chance when event planner Molly (ALICE EVE) accidentally leaves her phone at the airport security checkpoint, and he and Devon return it to her at a reception she's set up with her business partner, Patty (KRYSTEN RITTER).
Molly is the kind of beautiful young woman who turns heads and thus would seem to be completely out of Kirk's league. Yet, she takes a liking to him, probably because he's just about the polar opposite of her last boyfriend, Cam (GEOFF STULTS), a handsome and egotistical pilot. Kirk can't believe it, which also holds true for his stunned friends, but he and Molly soon become a romantic couple. From that point on, Kirk must not only deal with that disbelief, but also the nagging notion that he's not good enough for her.