The player takes the role of a protagonist known as Ranger who was sent into a portal in order to stop an enemy code-named "Quake". The government had been experimenting with teleportation technology and developed a working prototype called a "Slipgate"; the mysterious Quake compromised the Slipgate by connecting it with its own teleportation system, using it to send death squads to the "Human" dimension in order to test the martial capabilities of Humanity.