On the planet known as Arena World, giant monsters are used by the Arena Lords as gladiators to fight to death for the wagering and enjoyment of their crowd. In recent years, the muscled monster known as Gurral the Smasher had risen to the ranks of arena champion. So dominant are Gurral's victories that the crowd is losing interest in his battles. With crowd interest waning, the Arena Lords are desperate to find a monster who can offer their champion a challenge, lest they lose the crowd and with it their position of power. An enigmatic Newcomer approaches his fellow Arena Lords with the knowledge that rifts have been opening in the time space continuum. These rifts allow access to other worlds and dimensions. The Newcomer suggests that on one of these worlds is a beast who can challenge Gurral. A beast who has crushed dozens of other kaiju. A beast known as Atomic Rex!The Newcomer manipulates both the Arena Lords and Gurral into sending the Smasher to battle and capture Atomic Rex so that the nuclear therapod may fight in the arena! When Gurral travels to Atomic Rex's Earth a battle ensues between the two kaiju the likes of which the Arena Lords have never seen. As the monsters battle for supremacy the Newcomer's true motives and the dimension shattering reasons behind them will be revealed.