Mike Terry (CHIWETEL EJIOFOR) is a former military man turned self-defense instructor who runs Southside Jiu-jitsu with his wife, Sondra (ALICA BRAGA), in Los Angeles. Despite being good at what he does and having loyal students such as Snowflake (JOSE PABLO CANTILLO), who helps teach the class, and Joe Collins (MAX MARTINI), a local cop, Mike and Sondra are having a hard time keeping the business solvent.
Thus, when distraught lawyer Laura Black (EMILY MORTIMER) accidentally sideswipes Mike's truck and then, once inside and suffering from post traumatic stress disorder ends up shooting Joe's service revolver through the storefront window, things look particularly bleak.
Sondra has Mike visit her brother, Bruno Silva (RODRIGO SANTORO), a club owner and fight promoter, for a loan, but Mike isn't pleased that Bruno hasn't paid Joe who he had hired as a bouncer. He doesn't get anywhere with Bruno who wants Mike to fight professionally for him, but while at his bar he ends up saving movie action star Chet Frank (TIM ALLEN) from some thugs.
As a result, things look up when Chet has Mike and Sondra over for dinner with his wife, Zena (REBECCA PIDGEON) and producer Jerry (JOE MANTEGNA). Soon, Mike's been hired as a consultant on Chet's film, and Sondra borrows money from loan shark Richard (DAVID PAYMER) to finance her fabric business opportunity with Zena.
Things change for the worse, however, when a watch Mike gave Joe -- after receiving it from Chet as a "thank you" for saving him -- turns out to be hot. When Mike reports that to Jerry, that sets into motion a series of events that Mike couldn't have foreseen, including Jerry stealing part of Mike's training regimen and selling that to fight promoter Marty Brown (RICKY JAY).
From that point on, Mike must figure out how to react and whether he should allow himself to be manipulated into fighting in a mixed martial arts competition.