The story incorporates references from the past to the present, religion and conspiracies into the game. A sequel, Assassin's Creed II, was released in November 2009.
Set in the future and the far past, the story of Assassin's Creed follows Desmond Miles, who is forced to re-live his ancestor's memories through a machine called The Animus: Altaïr Ibn La-Ahad (The Flying Eagle, Son of None), a member of an elite group of assassins known as the Asaslasashin. Altaïr, in the beginning of the game, is a cocky arrogant assassin that stubbornly prefers to do things his own way.
After disobeying the Assassin's Creed, Altair is demoted. He is sent to prove himself by investigating a traitor in Masyaf, his hometown and location of the Asaslasashin, who let Templar Knights from an enemy country through the gates.
After this, Altaïr earns the right to wield a blade. Throughout the game, he must investigate and assassinate nine people who are related to the cause of the third crusade. As he goes through the story, with each person he kills, he has a weapon or ability restored to him. After each assassination, it becomes clearer to Altair that something else is going on.