Jack scales a high mountain as he continues on his quest. Fighting against the wind, he moves along a narrow ledge and finally comes to a narrow crevasse. Moving along it, Jack finally emerges into sunlight once more and continues climbing. Below he watches a great battle between two armies. The defending Spartans fire their spears against the enemy bull robots until the two sides clash directly. The Spartans kill hundreds of the enemy, but more replace them. When one brave warrior is overrun, Jack can take no more and leaps to his side. Together they defeat the attackers and the survivors drag off their survivors.
When Jack says that the Spartans have won, his new friend Brotok takes him to the king to explain. They move past the injured Spartans, all too weary to move. However, when the king arrives, they all stand in honor of their leader. King Spartok goes to his son, Kurtok, who confirms that they held their position. Spartok worries that they will not survive another attack, but Kurtok vows that they will fight to the end and his father says that knows they will not fail them.
Spartok moves to his throne and asks Brotok who Jack is. Brotok explains what happened and Spartok wonders why Jack intervened. Jack apologizes for intervening and prepares to leave, and Spartok apologizes in turn for his rudeness brought on by years of war. When Jack wonders why they are fighting, Spartok explains that years ago a mechanical Beast went mad and wages war against all in its path. The creature feeds off of the land itself, taking all of Spartok's neighboring countries. The Spartans are the last, and the Beast wants their land. Their land has survived because it is protected by high mountains and only a single narrow ravine gives access. Spartok and three hundred of his men fought there and stopped the Beast's army despite their superior numbers. However, the war has gone on for years and the Beast's army is infinite because it recycles its fallen robots and sends them back anew. Spartok is the fifth king to defend the gateway.
The king warns Jack that the next day's battle will bring the same stalemate. However, the samurai tells them that he found a path through the mountains, and offers to show it to them. Spartok declares that he and 50 of his men will go through the ravine and attack the Beast directly, while the other 250 hold the position. As the soldiers retire for the night, Spartok tells Kurtok that he must stay there because if anything happens to him, Kurtok will become king.
The next day, the Spartans arm themselves and prepare for what they hope will be the final battle. Spartok and his men inch through the narrow ravine one at a time, Jack leading the way. When they come out the other side, they rappel down the mountain.
At the Spartan camp, Kurtok dons his armor and goes out to rally his men.
Jack, Spartok, and the fifty march on until they reach the Beast's mechanical fortress. The bull robots leave and Spartok leads the charge into the fortress.
Kurtok and his soldiers take up position to block the entrance to their lands. The Beast's army charges toward them and the Spartans ready their spears. When the robots come in range, the Spartans fire and the first wave of robots is wiped out. However, they keep coming, closing to hand-to-hand.
Spartok and the others create a shield formation as the robots attack them. Once they have destroyed the first wave of robots, they disperse and take the battle to the enemy. Jack destroys a robot with every blow and Spartok is his equal.
Once they have destroyed the enemy, Spartok and Jack run into the fortress, seeking out the Beast. The two warriors finally come to a vast chamber and climb down to the floor. As they approach the center, the spider-like Beast lowers itself from the ceiling behind them and attacks. They leap out of the way just in time and fend off its arms
Spartok's sword shatters on the Beast's metal skin, and Jack throws the king his katana. Spartok throws Jack his shield in return, and together the two of them drive off the Beast momentarily. It leaps onto the ceiling and then attacks anew, knocking Jack back. As it advances on Spartok, the king throws Jack's sword into its head and out the other side. As it explodes, Jack leaps in front of Spartok, shielding him with his body.
Outside, the bull robots explode as their master "dies." Spartok runs out of the fortress as it explodes behind him.
Many years later, a now-elderly Spartok tells his people that they never found Jack. The only thing they found was his shield. However, Spartok is sure that such a great warrior could not be stopped so easily, and is confident that Jack survived the conflagration.