down a narrow ravine blanketed by a dense mist. The surrounding forest is eerily silent as they enter and are obscured by swirling vapour. Later, having found nothing around the clearing, the support party is also following the trail. By sunset, they have reached the ravine. The team leader reports to Carter that they are approaching an area of mist and hope to catch up with Koenig before dark. They, too, walk down the passage and into the mist... On Moonbase, Bergman attempts to call Koenig, but gets no response. Carter reports that he, too, is unable to contact the Commander. At their geographic latitude, the night will last only two hours; Carter decides to land and commence searching for the others at daybreak. Sandra claims to see something moving in the fading light, but Carter cannot confirm her sighting. He brings the ship down next to Eagle One. As Carter and Sandra settle in for the night, a trio of cavemen watches the ship from the bushes outside. The next morning, Sandra awakens to find Carter gone. Having left early to scout the area, the astronaut has reached Koenig's moon buggy by the time a concerned Sandra calls. He jokes that all her fussing will make her boyfriend Paul Morrow jealous. Signing off, he follows the markers, but veers from the designated trail to take a short-cut through tall grass—and falls head-first into a camouflaged pit. When Sandra tries to call again, she receives no answer. Nervous, she contacts Alpha. Morrow consoles her with the news that Bergman is flying down to lead a new search mission. Carter comes to. Trapped at the bottom of a ten-foot-deep pit, he begins to dig hand- and foot-holds into the soft clay walls. His work is interrupted by the three cavemen. Their spear-carrying leader leaps on Carter like a wild animal. In the ensuing brawl, the astronaut is beaten senseless. As the caveman raises his spear to finish him off, he is startled by the buzzing ring-tone of Carter's commlock. Fumbling with the device, the spear-man is intrigued by Sandra's image on the tiny TV monitor. Getting no response, she stops calling—her sudden 'absence' angering the spear-man. Using a tree trunk lowered by his comrades, he clambers out of the pit and shambles off toward the Eagles. Ten minutes out from Retha, Bergman calls Sandra from Eagle Three. After laying out a