Stingray, a highly sophisticated submarine built for speed and manoeuvrability, is the flagship of the World Aquanaut Security Patrol (WASP), a 21st century security organisation based at Marineville in the year 2065, located somewhere near the west coast of the United States. In case of an attack the entire city can be lowered into the ground on hydraulic jacks. Marineville is 20 miles (32 km) inland, and Stingray is launched from the base's "Pen 3" through a tunnel leading to the Pacific Ocean. "Action Stations", "Launch Stations" and "Battle Stations" are sounded not by sirens but by recordings of Native American-style drumming (composed and recorded by series composer Barry Gray).
The pilot of Stingray is the square-jawed Captain Troy Tempest (modelled on James Garner), accompanied by Dixie navigator "Phones", so called because of his skill at interpreting hydrophone bleeps. (His real name, George Sheridan, is referred to in the show's publicity but never spoken on-screen). Troy and Phones board Stingray by sitting in their command chairs which are lowered into the submarine on long poles. They take their orders from the crusty wheelchair-bound Commander Sam Shore, whose daughter Atlanta Shore is also a WASP operative and enamoured of Troy.
During the course of the series Stingray encounters lots of underwater races, hostile and otherwise. The "Aquaphibians", a submarine warrior race, appear frequently, often under the command of King Titan of Titanica (modelled on Laurence Olivier). In the pilot episode, Stingray is attacked by Titan's forces and Troy and Phones are captured. They are rescued by Titan's slave girl Marina (modelled on Brigitte Bardot), a beautiful mute young woman who can breathe underwater. Troy is immediately smitten with Marina, and Atlanta becomes jealous. Meanwhile Titan swears revenge for Marina's betrayal. Marina becomes a regular member of Stingray's crew, and later acquires a seal pup called Oink, who features in a number of episodes.
Many subsequent episodes involve Titan's schemes to destroy Stingray and Marineville. These often fail due to the incompetence of Titan's surface spy, Agent X-2-Zero (modelled on Claude Rains[citation needed], but sounding like Peter Lorre).