The agents of the FBI (Bruce Willis and Radha Mitchell) investigate the mysterious murder of a university student, related with the man who helped to create a phenomenon of technological "substitution" that allows people to buy perfect proper robotic versions of themselves - apt and well similar, controlled machines for remote control, that later assume its lives - making possible to each one to enjoy life, indirectly, through the comfort and security of them houses. The homicide unchains an inquiry to get answers: in a world of masks, who is real? And who can we trust?