Three brothers Samuel, Jeffrey and Michael Douglas visits with their warrior, Mori Shintaro whom the boys optionally refer to as Grandpa, for its summer. Mori is Ninjutsu and a highly proficient in the fields of both Martial arts, and he has coached the boys in his or her techniques. After an organized crime ring proves to be too much for the FBI, it's time to get the 3 brother NINJAS! To make use of their martial arts skills, they team up to battle with the offense ring and outwit some kidnappers that are persistent!