Three families hiking the remote parashant Colorado river basin spots a hidden alien ship . a monstrous reptilian alien is playing with a baby alien . this opening, overlaps with an approaching group of military specialists tasked with capturing, or killing the alien, and killing any witness's. The soldiers engage the alien who;s a formidable foe . It begins fighting and eating soldiers and perusing our hero's . The group makes it to some caves where the alien cannot reach them, but now they're trapped . They discover other caves connecting various openings . A terrifying night ensues, fending off the soldiers and foiling the alien . One of the men manages to sneak down to the river where he lures the alien into plunging after him into the water, where it drowns . the group assembles next to the river with the one remaining soldier only to discover, another alien has been trying to get to them . they plunge into the river . A small craft comes flying from the space ship, revealing HE is the real alien . The monster the group was battling was a PET!