Amnesia is a sci-fi themed text adventure style game.
The game begins as the player's character awakens in a midtown Manhattan hotel room with absolutely no memory. He has no clothes and no money, and doesn't even remember what he looks like. The player soon discovers he is engaged to a woman he cannot remember, a strange man is trying to kill him, and the state of Texas wants him for murder. From here, the player must unravel the events in his life that led him to this point.
Source: Wikipedia, "Amnesia (computer game)," available under the CC-BY-SA License.