As it is ready to land, the plane of a secret expedition lead by the Doctor Samuel Leon crushes in emergency on the beach of a South Pacific Island. Thanks to the great experience of its pilot, Lauren Mercer, an ancient test pilot now working for herself, the members of the exploration team are all alive and safe.
Leon and his assistant Susana are searching for the source of a deadly virus contracted by a missionary on this same island. Accompanied by three ancient marine corps, Bear and Reyes under the commandment of Valentine, a famous spider scientist, Henry Capri and a native guide, the expedition directs to a little small indigenous village in the middle of the jungle. Leon suspects that the virus discovered had been produced by an unknown spider. Arriving in the village, this one is completely deserted and abandoned. While Reyes finds death in atrocious sufferings, provoked by ticks that have installed under his epidermis, the group is attacked by a frightful unidentified enemy. Valentine, who is in charge of the security of the members of the expedition, decides to step back in the next morning, having nothing more to hope in this mission. But Mercer doesn't share his opinion.
Lauren Mercer confesses and explains Valentine her real intentions: her brother, Lightfoot, also a test pilot, disappeared in this jungle several months ago while he was flying a mission on an experimental military craft. Mercer is well decided to find her brother. But what she does not know, are the circumstances in which he crushed. As he was in the pursuit of an alien spaceship, the former finally hit it and after the crash, an entity had propagated on the island, killing the poor pilot. Valentine promises Mercer to help her to find her brother if she helps the expedition to return back to the plane.
On their way back, the spider scientist Henry Capri discovers the remains of the thing that attacked them the day before. It concerns in fact a mutant that possesses characteristics of spiders and snakes. But his curiosity will drive him to death after explaining to the other members that the thing, a giant spider,
couldn't have grown on earth. From now, the terrible beast enters a hunt for the group of humans...
Click to read the end of the story. Spoiler ahead !
After discovering the remains of her brothers's body, Mercer understands that the beast is terribly dangerous. The former attacks the expedition. The Doctor Samuel Leon finds death, horribly digested by the spider. Despite a shelter of griddles, her assistant Susana will not survive any more. Out of ammunitions, Valentine and Mercer escape by a underground tunnel built by Japanese during the war. This one leads them in full in the nest of the thing that has begun to reproduce.
After a hard struggle for each kind to survive, the monster is finally killed. But our heroes who walk back to the coast didn't notice that something is observing them!