Submarine Super 99

A scientist named Dr. Oki, who created a new submarine model, has disappeared. His son, Susumu, suspects a hidden group is involved in a conspiracy. He is knowledgeable about the submarine, "Super 99," including its weapons and capabilities. Susumu believes finding his father means uncovering the secret group, the Helmet Party, and stopping their plans. With assistance from friends and the Marine Corps, he embarks on a dangerous underwater mission.