The sticky comic premise to "The Ex" is built around a wildly escalating romantic rivalry between two men, one of whom is in a wheelchair.

Zach Braff stars as Tom, a guy who abandons his career as a New York chef and retreats to the hometown of his wife (Amanda Peet) in Ohio, where he takes a job with an advertising agency managed by her father (Charles Grodin).

It's a wacky firm owned by a New Age-y guru (Donal Logue) who encourages workers to toss around an imaginary idea ball and issue apologies on Post-it notes in lieu of uttering them aloud.

All this drives Tom crazy, but he has a bigger problem - his backstabbling boss Chip (Jason Bateman), a paraplegic, is also his wife's high-achieving high school boyfriend. Chip is quietly sabotaging Tom's work in hopes of breaking up his marriage and catching Peet on the rebound.

"The Ex" develops as a no-holds-barred war of one-upmanship between the two men, with the overmatched Tom defeated at nearly every turn.

Here, the movie addresses an interesting subject - Chip consistently outsmarts and outmaneuvers Tom, and yet Tom pities him. Chip finds this particularly insulting, and says so.

Through Chip, "The Ex" wonders if acceptance of the physically challenged has progressed to the point where they can be as flawed and foibled (i.e., just as nasty) as the rest of us. It's a minefield for comedy, and director Jesse Peretz does a decent job of walking a tricky line, until he seems to lose his nerve.

The result is a wildly uneven movie, with some big laughs here and there. For the most part, though, it looks like the kind of concept comedy that was pitched to Ben Stiller, Will Ferrell, Vince Vaughn or Owen Wilson, and didn't quite make the cut.

It has some of the stock supporting players (Paul Rudd, Romany Malco from "The 40 Year-Old Virgin" and "Blades of Glory"), but not the A-list leads. Instead we've got Braff, who chooses to play Tom with a kind of wounded neediness that's frankly not all that funny.

Bateman, though, accustomed to cameos in "Dodgeball" or "The Break-up," does a nice job with a substantial and conceptually treacherous role. *

Produced by Anthony Bregman, Marc Butan, Anne Carey and Ted Hope, directed by Jesse Peretz, written by David Guion and Michael Handelman, music by Ed Shearmur, distributed by the Weinstein Co.