A businessman on a trip to Tokyo ends up in the middle of a centuries old feud between a criminal Ninja cult and a Samurai when he witnesses a assassination performed by the Ninja-cult leader.

During a commemoration for Japanese soldiers fighting in the US Army during World War II, Mr. Miyagi meets the widow of his commanding officer. He gets to know her granddaughter Julie, an angry teenager who is still feeling the pain of losing both her parents in an accident and is having problems with her grandmother and her fellow pupils. Mr. Miyagi decides to teach her karate to get her through her pain and issues and back on the right path.

Jeff, a young delinquent, is enrolled by his father in a kenpo school, in the hopes of teaching the boy some self-discipline. Years later, Jeff’s mentor, Kim, is being threatened by one of the Korean mafia families. Jeff tries to help his old friend, but is too late to prevent Kim’s death at the hands of an unknown hitman. Vowing revenge, Jeff takes on all of the families, using his martial arts skills to find the man who killed his friend.