Taking the role of the protagonist from the first game's hero, Nomad, Alcatraz is a US Marine who is sent into New York City, now occupied by the alien Ceph, to extract Gould and take him to safety. However his submarine is attacked by the Ceph and he is washed up on the shore of New York where he is rescued by Prophet and given the Nanosuit 2.0.
Much about Alcatraz is unknown, even his real name. Unfortunately, unlike Nomad from the original Crysis, and Psycho from the expansion Crysis: Warhead, Alcatraz is a silent protagonist.
The nanosuit he wears becomes much more important throughout the game when he becomes infected with the bio-weapon the Ceph are using. Alcatraz must fight to stay alive while his suit creates a cure/weapon to be used against the Ceph and their own bio-weapon.