"Kingdom" is a multi-part sports drama that tells the story of the rise and fall of participants in mixed martial arts fights. The action revolves around the couple Alvi and Lisa, who together open a gym that trains future champions in MMA. However, things are not going well for them - all hope is placed on their eldest son, who has the potential to become an excellent fighter. The younger son also trains at the gym, but he has major drug problems. Because of his destructive addiction, he severely damages his relationships with his family. The situation changes when Lisa's ex-boyfriend, Ryan, returns to Los Angeles. Many years ago, he was a legend in the octagon but ruined his career because of drugs. Alvi wants Ryan to become his new coach.