meal, she opens the hatch to observe their arrival—and is surprised to find the spear-man waiting outside. He darts inside and, after a struggle, Sandra is carried off by her savage assailant. During this, Carter regains consciousness and climbs out of the pit using the trunk left by the cavemen. He makes for the landing site as Eagle Three sets down. When Bergman and Kano enter Eagle Two, they find only their lunch waiting for them. Sandra and her captor arrive at the caves that house a small tribe of Stone-Age people. As the curious adults (there are no children) crowd around her, she attracts the attention of the caveman chief. After a brief scuffle with the spear-man, the chief claims Sandra for himself and drags her into his private lair, followed by his protesting mate. When they lean in close to observe her, Sandra shrieks, convinced she has gone mad. Despite their weather-beaten faces, rotten teeth and unkempt hair, the chief and his cave-wife are dead ringers for Koenig and Helena. That night, the spear-man steals across the cave to see Sandra. He presents her with a leopard skin, which she refuses. His offer becomes more vigorous and, in his attempt to make her to wear the skin, he tears off her uniform tunic. Her screams wake the chief, who charges out to do battle with the presumptuous spear-man. A vicious struggle ends with the chief lifting the spear-man over his head and hurling him into the fire pit. As the victor claims his prize, his mate—also the tribe's medicine woman—tends to the spear-man's burns. The chief finds Sandra has fashioned the pelt into a serviceable garment. He stalks her with amorous intent, but is distracted by the shiny medical monitor on her wrist. She takes this opportunity to bash him in the head with a rock and slip away into the night. The cave-wife, sensing something amiss, finds her mate alone, battered and insensate. Wailing, she gestures with Sandra's tunic—stained with his blood—and sends the men out to hunt down the escapee. Morning finds Bergman and party searching the forest for Sandra and the others. As they approach the mystery ravine, Carter grabs the moon buggy's control stick from Kano and swerves just before they enter the wall of mist. He reckons it must be involved in the disappearances. Everyone has passed this way, entered the mist and