The scholar Akronos has discovered the Geometric Nucleus during the course of his research. The Nucleus is a device of incredible power that could be a terrible weapon. Akronos feels that the Nucleus must be kept from evil men at all costs. When he learns that the evil warlord Zor and his army are approaching his castle, he asks his daughter Mila to bring his former student Ator back to help defeat Zor. Mila runs away to find Ator. Zor's soldiers enter and begin beating Akronos, but Zor angrily sends them away to maintain the image of a man who would only use violence if needed.
Mila is pursued by Zor's soldiers, and is wounded by them, but continues to stagger towards Ator's home. At last she arrives, and Ator uses his medical knowledge to heal her wound. She then is able to convince him she is the daughter of Akronos, and that her father is in terrible danger.
Mila, Ator, and Ator's Asiatic companion Thong begin the journey back to Akronos' castle, facing a variety of dangers along the way, including a group of cannibals, another group determined to sacrifice them to their god — which is a huge snake — and other soldiers.
Finally they make it back to the castle. While Mila and Thong sneak in the back way, Ator uses his knowledge of flight to quickly make a hang glider, which he flies over the castle, dropping bombs on Zor's soldiers. Having defeated most of Zor's forces, Ator takes on Zor himself and defeats him. Akronos convinces Ator to let Zor live to face trial, but when Ator steps away, Zor grabs a sword to threaten Ator, and Zor is killed by Thong.
Afterwards, Akronos gives the Geometric Nucleus to Ator. Ator tells Mila he has to leave, that his life is too dangerous to share with her. Mila says that she knows Ator must fight evil where ever it occurs. Ator leaves Thong behind to help take care of Mila and Akronos, and leaves. He takes the Nucleus to a distant land, where he destroys it in a massive nuclear detonation
- Miles O'Keeffe
- Lisa Foster
- David Cain Haughton
- Chen Wong
- Charles Borromel
- Nello Pazzafini
- Donald Hodson
- Stephan Soffer
- Osiride Pevarello
- The film was released in theaters as Ator the Invincible and later as Ator, the Blade Master. It received the name Cave Dwellers after it was re-edited by distributor Film Ventures International.
- The opening and closing credits for the FVI release uses footage from an unrelated film, the 1963 Italian fantasy film Taur, the Mighty.
- This movie is the sequel to 1982's Ator, the Fighting Eagle, which became a RiffTrax presentation in 2017 and would be used by MST3K in Season 12 as Experiment #1206.
- It was followed by Iron Warrior (1987) and Quest for the Mighty Sword (1990).
- The "Ator" series was made to capitalize on the popularity of the Conan movies which starred Arnold Schwarzenegger.
- On Friday, September 23, 2016, this movie was featured on the MST3K-esque German TV show "The Worst Movies of all Times"  which is co-written and co-produced by comedian Oliver Kalkofe, who also co-wrote the German dialogue for Mystery Science Theater 3000: The Movie. On the show, Kalkofe and another comedian present movies and provide commentary & pop-up text during the film in much the same style as MST3K/RiffTrax/CT.