O criminoso El Topo desafia os invencíveis Quatro Mestres do Deserto pelo amor de uma mulher, e acaba vencendo. Seu nível de consciência aumenta, mas, entretanto, ele é traído pela mulher. Começando uma nova existência como homem santo, El Topo se compromete a libertar uma comunidade de excluídos.
Numa noite de tempestade, não podendo dormir por causa dos trovões e relâmpagos, o menino David MacLean, vê um disco voador aterrar atrás de uma colina próxima à sua casa. Seu pai, cientista, vai investigar. Ao regressar, comporta-se de maneira diferente, fria e hostil. O menino percebe uma marca incomum na nuca do pai e gradativamente se vai apercebendo que pessoas desaparecem atrás da colina, apresentam o mesmo comportamento estranho e a marca que seu pai. Isso o leva a concluir que há uma invasão alienígena acontecendo.
A polícia o prende e chama a Dra. Pat Blake , do Departamento de Saúde, para cuidar dele. Ela o ouve e, ao presenciar o encontro do menino com seus pais, compreende que ele pode estar falando a verdade. Ela consegue contato com o astrônomo Dr. Stuart Kelston (Arthur Franz)que acredita na história e contata o exército.
A student and her photographer boyfriend visit an island off of Massachusetts to research a hotel supposedly haunted by a witch.
A group of scientists travel to a remote island to study the effects of nuclear weapons tests, only to get stranded when their airplane mysteriously explodes. The team soon discovers that the tests have given rise to crabs mutated into intelligent, impervious, telepathic giants intent on increasing their numbers by breeding, then travelling to populated areas to feed, and which do not intend to be stopped by their discoverers.
A man with an unknown disease travels to an island with his girlfriend where his relatives once lived, hoping to find a cure to his illness. Although his relatives were all thought to be dead, he finds them living underground.
With the cyclotram, an atomic-powered rock-boring vehicle, Dr. Jerimiah Morley leads an expedition into a subterranean world.
The Three Mesquiteers are forced to track down a train robbery ring after some of the gang hijack their truck for a getaway and the police conclude they are part of the gang, an identification which is just fine with the gang's nameless chief.
While on a mission to locate three missing soldiers, a team of reconnaissance marines encounter a blood-spattered Iraqi stumbling through the desert. After following the distraught man into the depths of an insurgent cave, the marines make a horrifying discovery bringing them face-to-face with an ancient evil.
The Secret World of Og is a children's adventure about three young girls who venture into an underground cavern beneath their playhouse to look for their lost baby brother. There, they discover a land of little green people who are enamored by the world above but won't allow anyone to leave their cavern for fear they might "tell".
A woman leads an expedition into a remote jungle to find her long-lost brother, but instead finds a mad scientist who has created a fungus monster that feeds on the local inhabitants.