The full plot runs from a failed assassination in the desert to the fall of Memnon and the crowning of Mathayus as the Scorpion King.
Memnon, a conqueror, is overrunning the desert tribes with the help of a seer named Cassandra, whose visions let him foresee enemy moves. King Pheron hires three Akkadian assassins, Mathayus, his brother Jesup and their friend Rama, to kill her. Takmet betrays the plan, the Akkadians are ambushed, Rama is killed, Jesup is executed and Mathayus is left in the desert to die. He escapes with help from Arpid and swears to complete the mission.
Mathayus slips into Memnon's city of Gomorrah and finds Cassandra, but he chooses to take her with him instead of killing her. He fights off Memnon's men, including the captain Thorak, and is poisoned, but Cassandra heals him. The trio then looks for the explosives maker Philos and is captured by the rebel leader Balthazar. Mathayus defeats Balthazar, who then offers him shelter. Cassandra sees visions of danger, and she and Mathayus grow close.
Cassandra goes back to Memnon to try to kill him, while Mathayus, Balthazar, Arpid, Philos and the rebels attack the stronghold. Balthazar kills Takmet, Cassandra stops a guard from killing Mathayus, and Mathayus finishes Memnon with an arrow. Memnon's remaining soldiers yield, and Mathayus is named the Scorpion King.