Much light humor is made of showing Showalter as a "Baxter" in several typical romantic comedy clichés; for instance, he is shown being left at the altar as a former love is claimed by her high school sweetheart, and being left in college at a pep rally for an underdog sports hero. The plot revolves around the life of Elliot Sherman during the two weeks before his wedding, as he doggedly fights off the curse of his former Baxter role in relationships.
IFC Films financed the film and produced it with Plum Pictures. They gave the film a very limited release; it had a U.S. box office gross of $181,872.
Elliot (Michael Showalter), a tax accountant from Brooklyn, is a dependable though thoroughly average young man doomed to be the "Baxter", the nice guy who's bound to lose the girl to the leading man in romantic comedies. Losing three girlfriends to last-minute rekindled relationships with their ex-boyfriends has made Elliot wary of being abandoned yet again.
About a week before his wedding to his girlfriend, Caroline Swann (Elizabeth Banks), Elliot discovers that her high school beau, Bradley (Justin Theroux), is back in town. Elliot tries to keep himself composed, but even Caroline's reassurances do not convince him that her feelings for Bradley are buried. In the meantime, Elliot meets Cecil (Michelle Williams), his temporary secretary at his accounting firm. As he resigns himself to losing Caroline to Bradley, Cecil offers him a ray of hope: she does not believe in "Baxters" and thinks that his predicament is avoidable.
The two meet up again later that night at a small club where Cecil performs her original songs, and Cecil tells Elliot he needs to take more risks. When Cecil has a fight with her unsupportive boyfriend Dan (Paul Rudd), Elliot offers to put her up for the night. The next morning, Caroline shows up early with their wedding planner (Peter Dinklage) to finalize their plans. Elliot panics due to Cecil's hidden presence and during the meeting makes a string of awkward suggestions, upsetting Caroline, who begins to doubt his commitment to their relationship, to the point of calling off the wedding.
While out to a bar with his friends from work, Elliot accidentally runs into Dan, who recognizes him as Cecil's "Baxter" friend. Dan is there to meet with Sonya, who's Bradley's current girlfriend and Dan's old college friend. They all decide to sit together, much to Elliot's chagrin. Both Dan and Bradley laugh and joke with Elliot's friends, until one of them mentions that Caroline left him. Depressed and upset, Elliot leaves and contemplates suicide but he's interrupted by Caroline's brother-in-law, Louis (David Wain), who tells him Caroline is willing to give their engagement another chance.
Elliot plans a romantic dinner with Caroline, but finds her with an anguished Bradley, who just broke up with Sonya and is back flirting with Caroline. Caroline convinces Elliot to take Bradley out with them. They cancel Elliot's reservations to an expensive restaurant and go instead to a burger place that Bradley knows well. Elliot feels out-of-place and eventually calls Cecil from the back of the restaurant, confessing that he feels that his marriage will be over before it begins.
The next day, Elliot arrives at work to find that Cecil is his temp again. When she proposes to go have a drink together, Elliot explains that after his phone call, the night actually got better for him. As Caroline accused Elliot of being unromantic, he stood up for himself and accepted to go dance with her and Bradley, actually impressing Caroline with his moves. Bradley shows off his breakdance routines, accidentally hitting Elliot in the face, to Caroline's concerns. Bradley apologizes and reveals that he will leave the next morning to Malta for his work as a geode student.
Though happy for him, Cecil is saddened by the news because of her growing feelings for Elliot. She mentions that Dan is moving to Cincinnati and she's going to follow him there, to Elliot's discomfort.
At Caroline and Elliot's wedding, Bradley crashes the ceremony and declares his love for Caroline, a split second after Elliot was going to voice his own objection. Caroline finally gives in and kisses Bradley passionately in front of the whole church. Elliot takes off immediately to catch Cecil before she leaves town, and finds her at her apartment right while Dan is leaving. Elliot declares his love for her, and chases off an old friend of hers (Ken Marino) who suddenly showed up. Later, they perform together at the same club where they had their first date, with Cecil singing one of her songs and Elliot playing the piano to back her up.
In a mid-credits scene, Dan reflects in narration on his own status as a Baxter, having just lost the girl to the leading man.Michael Showalter as Elliot Sherman
Michelle Williams as Cecil Mills
Elizabeth Banks as Caroline Swann
Justin Theroux as Bradley Lake
Michael Ian Black as Ed
Zak Orth as Wendall Wimms
Peter Dinklage as Benson Hedges
Catherine Lloyd Burns as Stella
Katharine Powell as Sonya Simmons
Paul Rudd as Dan Abbott
Haviland Morris as Kate Swann Lewis
David Wain as Louis Lewis
A. D. Miles as Bar Baxter #1
Joe Lo Truglio as Bar Baxter #2
Seth Herzog as Bar Baxter #3
Jonathan Marc Sherman as Deaf Bar Baxter
Leslie Lyles as Sheila Sherman
Jim DeMarse as Leonard Sherman
Jon DeVries as Alan Swann
Donna Mitchell as Judy Swann
Sarah Drew as Serena
Ken Marino as Jack Mechanic
Jack McBrayer as Elliot's Friend (uncredited)
Rotten Tomatoes gives the film a critic rating of 32% and an audience rating of 75%.