The game begins with the player Eric Leblanc riding in an airplane with his son Timmy Leblanc when the plane mysteriously crashes on a remote island. The player and his son manage to survive the crash, but the player watches helplessly as his son is kidnapped by a man in red war paint. In addition to trying to survive in the wild and fending off hostile wildlife and feral, cannibalistic mutants, the player searches the peninsula for his son. The forest surface leaves clues to help the player puzzle out the story, but the majority of the plot takes place in the caves that riddle the underside of the peninsula.
Eventually, the player discovers an abandoned underground lab complex that was studying an artifact capable of bringing the dead back to life, but requires the sacrifice of a child. The player discovers that the kidnapper intended to sacrifice the player's son in order to revive his daughter. However, the player discovers that the daughter had mutated into an aggressive, cannibalistic monster, similar to the other mutants that roam the peninsula. The player confronts the child, who seizes and mutates further before attacking him, leading to the daughter's death. The player then attempts to use the daughter's body to revive his son, but the process is a failure, since a live sacrifice is needed. The player explores the lab further and discovers a second artifact that functions as a type of EMP device capable of bringing down nearby planes, implying that it is the cause of his own plane crash. The player then uses the artifact to cause another plane to crash, intending to find a sacrifice to revive his son.
One year later, the player and his son have apparently been rescued, and they are invited onto a talk show to promote a book that the player wrote, chronicling his experiences. However, during the show, the player's son collapses and begins to have a seizure, implying he is undergoing the same mutation that the daughter had.