Casey is attacked at random on the street and enlists in a local dojo led by a charismatic and mysterious Sensei in an effort to learn how to defend himself. What he uncovers is a sinister world of fraternity, violence and hypermasculinity and a woman fighting for her place in it.
| Actor | Role |
|---|---|
 Jesse EisenbergCasey | Casey |
 Alessandro NivolaSensei | Sensei |
 Imogen PootsAnna | Anna |
 Steve TeradaThomas | Thomas |
 David ZellnerHenry | Henry |
 Phillip Andre BotelloKennith | Kennith |
 Jason BurkeyAlex | Alex |
| MMike BrooksSteve | Steve |
 C.J. RushOther Steve | Other Steve |
 Davey JohnsonGun Store Owner | Gun Store Owner |
 Hauke BahrGrant | Grant |
| KKatherine MartinBakery Woman | Bakery Woman |
| CCameron MurphyNew White Belt | New White Belt |
 Nicholas HulstinePickup Truck Driver | Pickup Truck Driver |
| LLena FriedrichFrench Girl | French Girl |
 Louis Robert ThompsonVeterinarian | Veterinarian |
 Dallas EdwardsManuel | Manuel |
 Katherine Smith-RoddenStore Cashier | Store Cashier |
| FFrederic SpitzFrench Guy | French Guy |
 Alex HaydonMan Wearing Pants | Man Wearing Pants |
| MMark Sawyer-DaileyMan Reading Newspaper | Man Reading Newspaper |
 Leland OrserDetective McCallister | Detective McCallister |
 Josh FademSerial Killer | Serial Killer |
| SScott GoodmanDrunk Man | Drunk Man |
 Justin EatonLone Man | Lone Man |
 Caroline AmiguetFrench Audio Instructor (voice) (uncredited) | French Audio Instructor (voice) (uncredited) |