Sheena's white parents are killed while on Safari. She is raised by the mystical witch woman of an African tribe. When her foster mother is framed for the murder of a political leader, Sheena and a newsman, Vic Casey are forced to flee while pursued by the mercenaries hired by the real killer, who hopes to assume power. Sheena's ability to talk to the animals and knowledge of jungle lore give them a chance against the high tech weapons of the mercenaries.

The space shuttle Churchill is assigned to observe Halley's Comet under the command of Colonel Tom Carlsen. They see a strange form attached to the comet and Carlsen goes with a team to investigate. They find three humanoid life forms in caskets and they bring them to the Churchill. However, Earth loses contact with the shuttle and the Space Research Center sends another spacecraft to search the Churchill. They find the crew dead and the shuttle burnt and one rescue pod missing. They bring the...