"The Card Counter" follows William Tell (Oscar Isaac), a gambler and former serviceman who sets out to reform a young man seeking revenge on a mutual enemy from their past. Tell just wants to play cards. His spartan existence on the casino trail is shattered when he is approached by Cirk (Tye Sheridan), a vulnerable and angry young man seeking help to execute his plan for revenge on a military colonel (Willem Dafoe).

Tell sees a chance at redemption through his relationship with Cirk. Gaining backing from mysterious gambling financier La Linda (TIffany Haddish), Tell takes Cirk with him on the road, going from casino to casino until the unlikely trio set their sights on winning the World Series of poker in Las Vegas. But keeping Cirk on the straight-and-narrow proves impossible, dragging Tell back into the darkness of his past.