Deep Heat is the 27th production episode and the 19th Broadcast episode of the British television series Stingray.
The crew of Stingray go and investigate the disappearance of a sea probe, which has gone down into a volcano. In the volcano they find two Subterraneans desperate to escape from the volcano using any means necessary!
Deep in the ocean, an unmanned sea probe is being used by Marineville to create a survey of the sea. Soon the sea probe stumbles across an underwater extinct volcano, and it slowly descends into the mouth of the volcano. Because of this, the signal of sea probe begins to get fainter and fainter until it finally stops.
Commander Shore launches Stingray to investigate the disappearance of the sea probe. Stingray soon reaches the volcano but is suddenly pulled down into the crater by some force. They soon reach the bottom of the crater, two and a half miles down, where Stingray lands on a smooth surface.
Suddenly a voice instructs Troy and Phones to make there way to a door, which is apparently an airlock. Before they try to escape, missiles are aimed at Stingray.
Troy and Phones swim out of Stingray with breathing apparatus on into the airlock. The voice instructs them to push the lever on the wall. Suddenly the airlock begins to descend even further down into the volcano, until finally it reaches the bottom.
Troy and Phones discover a room with elaborate furniture, food, machines, and inscriptions on the wall. They soon meet two Subterraneans called Torata and Fragil. They explain they are part of a civilisation called Centrallius, who live in a city called Voldana in the volcano. They tell that the entire city was submerged in lava and everyone was killed. Luckily Turata and Fragil were locked in this room when the volcanic activity started, saving them and soon the activity subsided, until now. They say that the volcano has become active again and that lava will soon pour into this room if they don’t escape.
That is why they sucked in Sea Probe in order to escape, but they discovered it was full of instruments and were unable to escape in it. Then they found Stingray, they say they need a craft to escape in because they cannot breathe underwater and have no breathing apparatus.
Troy and Phones feel happy to take them back to Marineville to help them escape, but there is only one problem. There are only two sets of breathing apparatus, so at gun point Torata and Fragil take the apparatus and step into the airlock. Torata says one final thing to Troy and Phones, “We would not want to prolong your suffering, we are humane people.” Torata then shoots the protective door allowing the lava to seep into the room.
Soon the airlock reaches the top and Torata and Fragil swim out to Stingray. Inside, Marina sees them coming without Troy and Phones, so she closes the hatch, stopping them from getting in. Torata and Fragil decide to go back for Troy and Phones in the hope they will be able to open Stingray.
Down below, Troy and Phone notice the airlock returning. Once it arrives they knock Torata and Fragil out and enter the airlock. They speed back up to the top as the fire from the lava chases them. Once they reach the top they all enter Stingray and manage to escape the volcano before it erupts.
- The WASP Jazz Band are seen here playing at the Blue Lagoon nightspot prior to their featured appearance in Tune Of Danger.
- The Newsreader from Tom Thumb Tempest can be seen behind Troy, Phones, Marina and Atlanta in the bar at the start of the episode.
- This episode was later used in the compilation released video titled Invaders From The Deep.
- When Troy and Phones swim out to the airlock from Stingray, the missile are no where to be seen in the long shot of Stingray.
- Torata and Fragil seem to recover quite quickly from being hit on the head by medium size boulders.
- During one shot of the lava overflowing, a back drop rips causing a some railing to be seen.