Richard's wife Pat worries about his reduced paycheck, and being able to maintain their comfortable lifestyle. Richard and his chess guru friend, Arnie, wonder if Richard is going through a mid-life crisis.

On the first day of class, Richard is confronted by plenty of attitude from his student Jimmy, who is filled with anger and who sees no point in school. Renee's little brother Dawson comes to class after morning kindergarten is over; Richard realizes Renee baby sits Dawson half of each day, because there is nowhere else for Dawson to go.

Jimmy is forced by a gang to steal a bike. When he almost gets caught, he drops the bike and runs to hide amid a crowd of people watching and playing chess. He sees his teacher Mr. Mason playing fourteen opponents at once -- and beating them all! Jimmy has newfound respect for his teacher when Mason explains chess is like two armies going to war. Jimmy becomes fascinated with the game.

Police bring Kenya to school after picking her up in a crack house where her mother was arrested -- again. When she gets into class, she easily solves a math problem on the blackboard that had all the other children stumped. Mason gets the idea that these kids could gain an education and self esteem by learning chess.

The students are invigorated, but the principal is wary. Mason is not following the lesson plan, so how could the children be learning? Mason puts math problems on the blackboard and declares there will be no chess until the math assignment is done. The kids scramble to do the problems, using their new chess brain skills.

It is quickly apparent that chess is making a huge difference in the kids' lives. Attendance is better. Test scores and grades are higher. When the kids learn they can compete for prizes and trophies in chess tournaments, just like other sports, they show Richard they're willing to work even harder, to earn the chance to compete.

Their first tournament is at the opposing team's school - a private school filled with mostly wealthy white kids. The South Bronx students are highly distracted by the beautiful and well-equipped school and by their opponents' uniforms and skin color. One by one, the South Bronx kids lose to their opponents - all except five year-old Dawson, who easily wins his match.

Mason gives a pep talk to his disappointed team. Arnie comes to class to help them analyze their games. They practice hard. They may not have the rich kids' gear, but they decide they can at least have a team name, and they share a cheer for the Knights of the South Bronx!

Each one wins in the next tournament. The opponents' coach is very impressed with the performance of the kids, even more so when he finds out they don't have coaches or time clocks. He gives Mason $300 to buy the team time clocks. "They deserve it," he says. An elderly rich women is charmed by the enthusiasm of the children, and she asks to be kept informed of their progress.

Later that night Kenya confronts her mother about her drug use.

The team is improving, but Mason's wife is ready for him to get a real job. The bills are piling up and she doesn't want to give up her fancy lifestyle or fancy car. He reluctantly agrees. Later that night he gets a call from Jimmy's mother. She's hysterical. The gang that Jimmy has been trying to avoid has beaten him badly.

Pat accompanies Richard to Jimmy's house. After she sees the way her husband cares for this child and his family, she knows that teaching these kids is what he was meant to do.

Richard takes Jimmy to visit his estranged dad in prison. They play chess and reconnect. Later, Jimmy confronts the gang leader and tells him he has given his name and address to his dad's "murderer friend" who will be released from prison the next week. Now he has "back-up", and the gang will have to lay off him.

There remains only one final arena of competition for the young Knights to conquer - the Nationals! Mason has the Knights practice without their chess boards. If they want to have a chance to win the big tournament, they must learn to play the game in their heads!

However, principal Walker has bad news. The applications for the nationals have arrived. The registration fee is $75 per child, plus the airfare to Dallas. There's no way the school can afford the trip.

They decide to have a bake sale and alert the media. Hundreds show up, including celebrities. Kenya's mom, Dolly, arrives clean and sober. But they still don't have enough money.

The next day at school, Mason is about to tell the kids they will not be able to go to the Nationals. But before he can say it, the rich elderly woman shows up to pay the balance -- and then some.

Mason and the team are on their way to Dallas! But will they be able to triumph in their biggest challenge yet?