For decades the U.S. Government has covered up the existence of dozens of species of dangerous creatures that have been captured over the years. After building a small, secretive city on a remote island in the Pacific, these monsters were transported there to be studied.
In 2012, disaster struck and the island was evacuated. Now the inmates have taken over, and different species fight for control within the city walls. But something extremely valuable was left behind, and the only way to recover it is by sending an elite mercenary unit into the most dangerous place in the world: Monster Island.