The story follows Callum Lynch (Fassbender), a death-row inmate who is rescued by a secret organization known as the Abstergo Foundation. Unbeknownst to him, the Abstergo is a front for the modern-day Templar Order, an organization that seeks to control the world through the use of the Apple of Eden, a powerful artifact capable of controlling human free will.

Callum is forced to participate in an experimental procedure involving the Animus, a machine that allows users to experience the genetic memories of their ancestors. Through this process, Callum is transported to 15th-century Spain, where he relives the memories of his ancestor Aguilar de Nerha, a skilled Assassin during the Spanish Inquisition. As Callum dives deeper into Aguilar’s life, he uncovers the secrets of the Assassins, a group sworn to fight for freedom against the Templars’ authoritarian control.

In the past, Aguilar is engaged in a covert struggle against the Templars, led by the merciless Inquisitor (played by Jeremy Irons). As the conflict escalates, the Assassins and Templars wage a secret war for the Apple of Eden, with Aguilar and his fellow Assassins determined to protect it and maintain humanity’s freedom.

Back in the present, Callum begins to unravel the connection between his own life and the ancient conflict. He starts to question his role within the Abstergo Foundation and the ethical implications of using the Animus to manipulate people. As he delves deeper into his ancestor’s memories, Callum becomes conflicted about whether to follow the path of the Assassins or the Templars, struggling with his personal motivations and the world’s larger moral battle.

The film’s action sequences are intense, featuring breathtaking parkour-inspired combat, sword fights, and daring rooftop chases that pay homage to the game’s iconic movement and fluidity. The historical setting of 15th-century Spain adds a layer of intrigue and depth, highlighting the tension of the Spanish Inquisition and the brutal politics of the time.