The Stingray crew track the launch site of missiles fired on Marineville to a volcanic island. However, on investigating they become captured by the aliens responsible.

Commander Shore and Phones are taken prisoner by Idotee who uses an old Spanish galleon to attack ships. Shore demands that Troy launch Sting Missiles against the galleon but the Captain disobeys orders and boards the vessel. There he opens his air cyclinders in the control room but unknown to Idotee the cylinders are filled with laughing gas! The alien is laughing so hard he fails to realise that he's captured

Thinking all the commotion at Marineville signals the visit of a VIP, X20 kidnaps the man and delivers him to Titan. The undersea ruler is surprised to learn that X20 has brought Duke Dexter, a pop singer. Titan is convinced that Dexter is an ally of the underwater people by the way he drives the Terraneans crazy with the weird noises he emits. Dexter is freed by Titan to continue his 'good work'.

Lt. Fisher takes command of Stingray in his training to become an Aquanaut. The exercise involves target practice on a Terror Fish target but X20 has attached a sticker bomb to one of the targets and one to Stingray's hull. Troy is air-dropped into the sea in an attempt to remove the bomb from Stingray's hull before it explodes.

Disaster strikes when a pilot on approach to a new airfield crashes because the light of a closed lighthouse mysteriously comes on again, confusing the pilot. When the old lighthouse keeper returns to investigate, he is captured by an alien race who use the lighthouse's power to provide energy for their city. It takes the crew of Stingray th free the keeper and see to the survival of the city.

After a man found in a coma is brought into Marineville, the staff are soon found in a trance like state. Can this be connected with the man?

While the Stingray crew are on shore leave in Casablanca, a merchant sells Phones a map leading to ancient treasure. However, when Troy refuses to search for it, Marina secretly alters Stingray's course.

A film crew arrive at Marineville to make a movie on Stingray. Everyone will play themselves except Troy, who is to be replaced by an actor. What's worse is that the director is in fact Surface Agent X20 who has a plan to kill Troy !!

The Stingray crew is captured when aliens set up a trap at a weather station. During what appears routine questioning, they unsuspectingly give away vital secrets about Marineville. While Stingray is on patrol, the base is attacked from below. The Invaders are unaware that Troy is aware of the invasion and they are taken by surprise when Stingray comes to the rescue.

Atlanta is taken captive by the crazed professor Cordo who rules a race of innocent underwater people. When Stingray arrives at his undersea farm he decoys Troy and Phones into a mock-up of Stingray while his subjects take command of the real craft and head for Marineville. Troy and Phones manage to overpower the professor in time to force him to recall Stingray before the creatures can launch their attack.

Following the escape of his slave Marina, Titan plots revenge by planning to kill the Stingray crew with a deadly plant that gives off toxic fumes. Meanwhile, Marina is feeling homesick.

During a Terror Fish attack, Stingray is damaged. When Troy goes to make repairs, an Aquaphibian poisons him with some purple liquid. At Marineville, the doctors can't find a cure. Without treatment, troy will die within four hours. Titan has the antidote but will only send it exchange for Marina. Commander Shore refuses but Marina makes up her mind and returns to Titanica. Titan keeps his word and sends the antidote. Once recovered, Troy must come up with a plan to rescue Marina.

Commander Shore is framed when a piece of equipment disappears from Marineville control. Troy places the commander under arrest but who would want to frame the commander and why doesn't Shore protest his innocence?