A secret experiment by a group of scientists turned into a disaster. Two unprecedentedly brutal murders occurred on a small tropical island. The government that oversaw the experiment urgently stopped it. The participants, who signed non-disclosure papers, returned home. Moreover, they are now officially prohibited from having contact with each other with a friend. But the nightmare that began on the island continues. Someone is killing the survivors - one by one. He kills just as brutally and bloodily as he did then. Who is this killer? Or perhaps it would be better to say - WHAT IS IT? Scientists, having violated the ban, get together again. They gather to begin their own investigation. Their lives are at stake. And perhaps not only her...