During the first closed-door demonstration of an amazing new virtual reality game called eXistenZ, the system's brilliant designer, Allegra Geller, is violently attacked by a crazed assassin intent on killing her and destroying her creation. Forced into hiding, Allegra enlists a young assistant to help her in testing the damaged system by convincing him to join her inside eXistenZ. The action explodes as their world's real-life dangers begin to merge with the fantasy of the game.