When Net Force Explorer Madeline 'Maj' Green crashes while piloting an XB-70 Valkyrie supersonic bomber, it isn't a matter of life or death - the plane is only a virtual simulation and the sabotage is only a prank by another member of her 'simming' group. But the prankster has other, more deadly ideas. He's about to take the idea of a computer virus into the world of virtual reality, and Maj is about to find that her virtual persona is in real danger.