Coded Arms takes place in an abandoned virtual reality system and its portal site inside a giant computer network. The VR system was originally created as a combat training simulator in the event of an alien invasion. However, during the development of the simulation program, a major flaw was discovered and development was cancelled and left abandoned. During this time when the program was not monitored, it kept evolving within the computer network and eventually turned into a vast and brutal VR world populated with virtual alien invaders, dangerous computer bugs and the VR system's own security bots.