A top secret U.S. government laboratory makes experiments with a curious amphibious creature captured in Amazonia. The scientists know very little about this humanoid – local tribesmen worship him as a god, he can breathe both on land and under water and is considered to be dangerous. When mute Elisa working in the laboratory as a cleaner randomly discovers the imprisoned creature, the two seem to be able to communicate. They don’t need words, gestures and emotions are just enough. When further brutal experiments are just about to start, Elisa realizes it’s time for them to escape.