Arácnea's residents have been desperately searching for a source of food to save the life of their queen (a big spider). Earth is chosen, since human brains are apparently like health food for alien spiders.

En la remota galaxia Aracnia, donde viven los aracnios, rige la Reina Aracnia que se alimenta con los cerebros de seres de otros planetas. Como los cerebritos escasean (aún no descubrieron la manera de preveer la desforestación), los aracnios deben salir a bordo de sus platillos voladores para buscar materia prima para su reina en planetas lejanos. Los arácnios detectan que en la Tierra viven personas que tienen cerebros poderosos. El luchador enmascarado Blue Demon debe enfrentarse a esta invasión de arañas extraterrestres .

Aliens from the galaxy Arachnea invade Mexico, seeking human brains to feed their queen, a monstrous spider. Aware of Blue Demon’s role as a champion of justice, the Arachneans take human form and try to eliminate him in various ways (including taking him on in the wrestling arena), none of which succeed. After a failed attack on Blue’s pal Hilda, she seeks out the alien’s underground lair and is snared in the queen spider’s web. Hilda’s boyfriend José is kidnapped by the aliens and prepared for brain extraction. Blue Demon must save them both and put an end to the alien’s evil plans on Earth.