After a mechanical failure aboard the spaceship Odyssey, Captain Lee Norsythe (Louie Lawless) is forced to crash land on a planet with atmosphere and conditions much like that of Earth, although it is many light-years away. As the ship sinks into the lake that it landed in, communications officer Cindy (Mary Appleseth) realizes that she forgot the radio in the ship and attempts to retrieve it, with the assistance of fellow crew-member Chuck (Chuck Pennington). En route, Cindy is attacked and killed by an unidentified aquatic creature, prompting Chuck to return to shore without the radio.
Realizing that they are stranded, the remaining eight people aboard the ship decide that survival is their primary goal and begin to explore the planet that they have landed on. Derna Lee (Derna Wylde) slipped while going through a swamp dropping the laser gun that Mike (Max Thayer) had given her in the water rendering the gun unusable. Thus, leaving the stranded individuals with one less weapon. They eventually come across a |Brontosaurus]], which leads them to deduce that the planet is following a similar evolutionary track as Earth, but is millions of years younger. Later, Charlotte (Charlotte Speer) determines that the plant life, especially the berries, is poisonous. After another dinosaur encounter, Lee decides that the best option is to climb the mountains and reach a higher plateau, where he believes the large creatures will be unable to reach them.
During the ascent, Nyla (Pamela Bottaro) slips and loses the entire supply of food rations, which Lee refuses to retrieve. Near a cave higher up the mountain, Vice-President of Spaceways Incorporated Harvey Baylor (Harvey Shain) discovers a nest full of eggs. After stealing an egg, Harvey is attacked and killed by a Centrosaurus. Soon after, much to ship engineer Jim's (James Whitworth) dismay, Lee decides to halt the expedition and settle at what he considers to be a defensible area. Lee expects to hold out until they are rescued, but Jim believes them to be trapped forever on the planet, and advises that they begin a new civilization. Lee triumphs and the remaining crew begin to build a defensive stockade around a cave. After several more encounters, a large Tyrannosaurus arrives and kills Derna, demolishing the stockade in the process.
The crew finally agrees with Jim that the best way to survive is to kill the predator. Their first plan, devised by Lee, is to attempt to poison the dinosaur by smearing berries on a dead Polacanthus and leave it outside of the Tyrannosaurus's lair. The plan backfires when the beast attacks from behind, killing Mike. Jim's plan is to set up large, wooden stakes and coat them in the poison, then lure the predator into them. After some initial troubles, including a fight between the T. rex and Rhedosaurus, the plan works, killing the Tyrannosaurus, which nearly takes Jim with it.
Years pass and the survivors have set up an agricultural settlement. Chuck and Charlotte now have a son. Charlotte wonders if they will ever be rescued, to which Nyla comments that it does not seem important anymore.
Who decides that the best option is to climb the mountains and reach a higher plateau?
Lee