In Assassin's Creed Origins, the story opens in Siwa, an Egyptian oasis town.
The protagonist, Bayek of Siwa, is a medjay who returns to his home region after a dangerous mission. Siwa establishes Bayek's identity, his relationship with Aya, and the personal motives that drive his campaign against the masked Order of the Ancients.
The game later expands across a large recreation of Ptolemaic Egypt, including Alexandria, Memphis, Cyrene, and the Giza area. Siwa is therefore not the game's only important location, but it is the setting that introduces Bayek and anchors his family history.
Origins is set in the first century BCE during the reign of Cleopatra VII and the political struggle involving Ptolemy XIII and Julius Caesar. Its narrative presents the formation of the Hidden Ones, the organization that later becomes the Assassin Brotherhood.