An expedition ventures into the perilous primeval Black Rainforest. Jack, a professional survival expert, foresees mutant monsters with black scales lurking in the woods and repeatedly warns the team to evacuate. However, his reminders are ridiculed and dismissed by the wealthy playboy William, rescue team captain Smith and other members.
The monsters soon emerge and launch a brutal hunt. William's girlfriend Sophia and quite a few team members are killed in succession. Jack flees and fights back together with his loyal assistant Bob and ecologist Rachel. They accidentally find out that these monsters are products of illegal biological experiments.
Blinded by greed and recklessness, the arrogant Smith and selfish William are slain by the monsters one after another. After a desperate battle and setting traps to gravely injure the beasts, the three survivors manage to escape the rainforest with severe injuries and get rescued. But the danger is not over. In the dark depths of the rainforest, countless monsters' vertical eyes glow faintly, and a new horror is lying in ambush.
