Marineville is targeted by a series of missiles fired from a seemingly uninhabited island, Stingray is sent to investigate but the crew are captured by an underwater race, who want information on Marineville's defenses.
| Actor | Role |
|---|---|
 Don MasonCaptain Troy Tempest (voice) | Captain Troy Tempest (voice) |
 Robert EastonLieutenant George Lee 'Phones' Sheridan (voice) | Lieutenant George Lee 'Phones' Sheridan (voice) |
 Ray BarrettCommander Sam Shore / Sub-Lieutenant John Horatio Fisher / Chidora (voice) | Commander Sam Shore / Sub-Lieutenant John Horatio Fisher / Chidora (voice) |
 Lois MaxwellLieutenant Atlanta Shore (voice) | Lieutenant Atlanta Shore (voice) |
 David GrahamNucella / Marineville Tracking Station / Jet Squadron Spearhead Leader (voice) | Nucella / Marineville Tracking Station / Jet Squadron Spearhead Leader (voice) |