Edward Dennison (Fonda) vanished four years ago while on an expedition to find an Alaskan passage leading into the center of the earth. His wealthy wife Martha (Pratt) hires anthropologist Jonathan Brock (Schroder) to find Edward, accompanied by his journalist nephew Abel (Grayhm) and Russian miner Sergei (Dopud) whose brother disappeared on the same journey. After discovering the passage, the four find it leads to an evolving prehistoric world and a primitive tribe that worships the now power-mad Edward. But a rival tribe could prove deadly to them all. Loose adaptation of the Jules Verne adventure.