Submarine Super 99(2003)

Submarine Super 99 is a classic anime series following young Susumu as he searches for his missing father, Dr. Oki, a brilliant scientist who designed an advanced submarine. When Susumu discovers evidence of a sinister plot by the secret organization Helmet Party, he realizes that finding his father is key to stopping their conspiracy. Armed with intimate knowledge of the Super 99 submarine and aided by loyal friends and the Marine Corps, Susumu embarks on a perilous underwater adventure. As he navigates treacherous waters and confronts dangerous enemies, the stakes grow higher with each mission. This thrilling sci-fi series blends action, mystery, and adventure as a determined young hero races against time to rescue his father and expose a global threat.