Original Japanese title: Kaitei no Gaadoman (海底のガードマン).
Bulma, Goku, and Krillin discover a secret underwater port at the heart of the Pirate Cave. And though the pirates are long gone, this port is far from abandoned! A ferocious sword-wielding robot lurks in the shadows, programmed to guard the pirates' treasure. And this metal monster isn't taking any prisoners!