3 Ninjas Kick Back

The three titular ninjas of the story, 13-year-old "Rocky", 12-year-old "Colt", and 7-year-old "Tum-Tum" are brothers experiencing the pressures of growing up. They frequently spend time training in the ninja arts with their grandfather, Mori Shintaro (Mori Tanaka in the previous film). Mori plans a trip for the four of them to Japan to take them to a martial arts tournament of which he was the champion fifty years ago. Only Tum-Tum seems interested in going, and even then, only out of interest in seeing sumo wrestlers due to how much food they get to eat.