

He travels to Athens, where he meets the scientist Archimedes, who leads the Athenian Resistance against the Romans. The Spartan is now more determined than ever to kill Tiberius and destroy the Empire.

After this conversation, the Spartan defeats the Hydra, awoken from its slumber by Sejanus to kill him. However the Spartans are informed by Sejanus that Sparta fell to the Romans in their absence, as they were not there to protect it. The Spartan fights his way out of the underworld against the dead of Troy and Sejanus's minions (living and undead), rejoining his allies, and then tries to leave the city. The Spartan again survives, and takes the spear of Achilles which his nemesis was armed with. Upon reaching the tomb of Achilles, the Spartan is once more confronted by Sejanus, who makes him fight his Nemesis, an exact copy of him who has the same abilities, and who knows the Spartan's every move and thought. Sejanus resurrects many undead Roman, Trojan and Greek warriors to kill the Spartan, but he fights his way through the ruins of the city, passing by the tombs of Priam, Hector and even the Trojan Horse. He fights his way to Achilles' tomb, where the spear is buried, along the way encountering Aelius Sejanus, the Praetorian Prefect, Tiberius' right-hand man, and a powerful necromancer. Upon their arrival at Troy, the Spartan enters the underworld of Troy, alone.

The Spartan travels through the Badlands north of Greece with Castor, Pollux and Electra to Troy, saving a village from barbarian warriors under the control of Beowulf, and recovering his hammer, Death-Biter, along the way. In the battle's aftermath, Ares once more speaks to the Spartan, and instructs him to go to the ruins of Troy and recover the spear of Achilles in order to save Sparta. As the Spartan army makes its last stand in the city ruins, the Spartan fights his way to the Roman headquarters in an abandoned temple, slays Crassus, and destroys the weapon, taking Crassus' enchanted sword and shield in the process. She is proved to be correct when the Romans attack with a weapon powered by Medusa, with the capability to turn entire phalanxes of troops into stone. Electra warns the Spartans that the Romans have a new, powerful weapon, capable of obliterating the city. He succeeds, aided by Castor, and in the process frees Electra, leader of the Amazons, and several other prisoners, before fighting their way out with the aid of Pollux and Spartan reinforcements. That night, Ares instructs the Spartan to infiltrate the Roman camp and recover the Blades of Athena, which the Romans had looted from the Parthenon in the conquest of Athens. The Spartans hold the Romans off long enough for the Spartan to destroy Talos using catapults.

The Romans are repelled, but the Roman General, Crassus sends Talos, a giant bronze man, to attack the walls. The Spartan (controlled by the player) fights alongside the Spartans, led by the brothers Castor and Pollux and their king, Leonidas, defending the walls. The Spartans prepare to go to war, and an unnamed Spartan is contacted by Ares, the God of War, who offers aid in the war against Rome and to help the Spartan uncover who he is. Most of Greece has been overrun by the Roman Empire, and only Sparta remains. The game takes place in the reign of Emperor Tiberius, and the war between the Romans and the Greeks. The story is told using a five-act, three-scene structure made popular by Ancient Greek plays.
