vanished. They opt to go around; on the other side, they come across the cave and hear a moaning dirge. The cave chief stands swaying before a shallow grave, half-dead and covered with gore, as his mate prepares him for burial. The arrival of the Alpha party disrupts the funerary ritual. As the women hide, the chief clumsily charges at the intruders. Bergman, too, is struck by the uncanny resemblance the wounded chief bears to the missing Koenig. As Carter prepares to shoot the savage, Bergman forces the astronaut's gun-arm upward and the laser blast goes wild. Startled by the pyrotechnics, the chief runs off. When Carter finds Sandra's tunic—stained with blood, he goes ballistic. Gun drawn, he vows to search the entire network of caves for her—and God help the savages if she has been harmed. Bergman and Kano take off after the chief, the professor convinced the resemblance is more than a coincidence. Tracks lead into the ravine and the men go round each way. Meeting up on the other side, they are shocked to find Koenig, sporting an ugly head contusion, sprawled unconscious on the ground just beyond the curtain of mist. Fearing cerebral haemorrhage, Bergman rushes Koenig up to Alpha; fortunately, it is nothing more serious than severe concussion. When the Commander regains consciousness, a relieved Bergman makes light of his suspicions of the cave chief being Koenig. Bob Mathias presents the results of the caveman's autopsy. He died of heart failure, frightened literally to death when trapped inside Eagle Six during lift-off. The doctor first thought him similar to Cro-Magnon man—until discovering he had capped teeth. Further examination revealed his identity to be that of the first reconnaissance team's pilot, Sandos...de-evolved 40,000 years by some phenomenon. They realise the professor may have been correct: if some unknown force was responsible for regressing Sandos into a caveman, it could have also transformed Koenig into the cave chief. Ignoring doctor's orders, the Commander flies back down to Retha to save Helena and the other transformed Alphans from Carter's wrath. During this, the cave-wife and her entourage have been skilfully evading Carter in the maze of tunnels. She returns to the main cavern in time to see that her posse has re-captured Sandra and are tying her spread-eagled to a frame used to dry animal skins. She howls in triumph. Carter follows the noise, and finds the vengeful