Oceanic Flight 815 out of Sydney, Australia, is mysteriously brought down out of the sky and crashes on an uncharted island somewhere in the Pacific Ocean. The survivors quickly learn they must band together if they have any hope of rescue, because the island is treacherous and holds many secrets.

Like the other castaways, the leading character has a tortured past that has brought him to the island. He suffers from amnesia and must find out who he is through playable flashbacks, interaction with the other castaways, and exploration of the island.