Assassin's Creed Origins is set mainly in Ancient Egypt during the Ptolemaic period.
The game follows Bayek of Siwa, a Medjay, and his wife Aya as they become involved in the origins of the Hidden Ones, the organization that later develops into the Assassin Brotherhood. The plot unfolds during the reign of Cleopatra and the political struggle involving Julius Caesar.
Origins depicts locations including Alexandria, Memphis, Siwa and the Giza plateau. Its setting combines Egyptian traditions with Greek and Roman political influence, reflecting the multicultural character of Ptolemaic Egypt.
The title is called Origins because it presents a fictionalized beginning for the Assassin organization rather than because the historical civilization itself began at that time. Assassin's Creed Odyssey, set in ancient Greece, came after Origins and uses a still earlier period.