Black Mesa is no more. Welcome to GargArena. The arena is our last chance to halt the invasion.

Mankind is facing a continued wave of portal storms that dump xenian life forms onto our planet. These creatures are growing in intelligence. They have started to make strategic assaults on humanity.

The smaller beasts are insignificant, but a new xenian threat has been dispatched. Dozens of the gargantuan monsters have been gathered into one unstoppable taskforce. As a unit, they take any outpost they desire.

The leader and manufacturers of this sudden xenian invasion are unknown. The gargs are storming our bases and claiming our supplies and technology.

Humanity has but one hope. Our scientists have developed a mechanical equivalent of the gargantuans. These robo-gargs are our last hope.