65 million years ago on the planet Somaris, pilot Mills is convinced by his wife to take on a two-year space expedition to earn the money needed to treat their daughter, Nevine's, illness. During the journey, his spaceship, the
Zoic, is hit by an unexpected mass of
asteroids and crash lands on an alien planet,
Earth. With his ship irreparably damaged, he discovers that his passengers have been killed while in cryogenically-induced sleep and contemplates suicide until he finds a lone survivor, a young girl named Koa, in her cryogenic pod. He sends a distress beacon for rescue and decides to take care of her. However, they have difficulty communicating due to language differences and a faulty translator. Mills later discovers a functioning escape shuttle from the
Zoic has landed on top of a mountain 15 kilometers away. To encourage Koa to follow him, he lies about her family being on the mountain, when in reality, they perished in the crash. The pair quickly realizes that Earth is inhabited by dangerous, aggressive alien creatures that are actually
dinosaurs. During their journey, they rescue a small armored dinosaur stuck in a
tar pit, which a pack of
theropods then slaughters. Mills plummets from a tree and manages to fight off a pack of
Lagosuchus attacking them. The two bond while spending the night in a cave, with Koa viewing several video messages from Nevine. They are soon attacked by a large, quadrupedal, carnivorous
archosaur, though Mills enrages it by shooting it in the eye before retreating further with Koa into the cave. They enter a narrow shaft to escape, but after a rockfall separates them, Mills is trapped inside the cave, while Koa falls outside the cave system into the open jungle. She is attacked by a
dromaeosaur, which she traps in a fallen tree log before slaying it with bombs he had given her earlier; he slaughters an
Oviraptor that had attacked him before escaping the cave, but falls into
quicksand while searching for her. Koa arrives and rescues him before they continue up the mountain. However, Mills discovers that a huge asteroid, the same one whose debris his ship crashed into, will strike Earth in less than 12 hours. When the pair reaches the escape shuttle, Koa angrily discovers that Mills lied to her about the death of her family, to which he apologetically reveals to Koa that his daughter Nevine had succumbed to her illness while he was away and promises to protect her. Upon learning that a rescue vessel will arrive soon, the two board the escape shuttle, but the asteroid's debris causes it to crash down the mountain. A pair of marauding
Tyrannosaurus rex harasses the two humanoids, though Mills successfully kills both of them after Koa distracts them with a projection of Nevine from one of her videos. Suddenly, the giant archosaur, which Mills had partially blinded earlier, appears from the jungle and pursues him. Encountering a large
geyser field, he manages to lure it to a geyser, but the geyser's water and steam only burn half of its face. As the angered archosaur prepares to kill him, Koa stabs it in its remaining eye with a large, sharp dinosaur tooth that she coated in poison berries earlier. The now-blind carnivore stumbles headfirst into a boiling geyser and is killed. The pair escapes just as the asteroids strike Earth, causing the cataclysmic
Cretaceous–Paleogene extinction event. The two relax as the escape pod travels into space towards the rescue vessel. During the closing titles, the evolution of Earth is shown, at the spot where Mills and Koa left, through an
ice age until the present day. ==Cast==