In this society, flying cameras are everywhere, watching and waiting to find any indiscretion.  Anyone who is outside the norm, or commits crimes against the state or a person, is sentenced to be "invisible" for a period of time.  They aren't really invisible, but are given a mark they can't remove or cover so that everyone knows that person is supposed to be ignored.  And I mean really ignored.  At one point the "invisible" man is badly beaten up by a gang, and he crawls home.  When he tries to call for medical help on his phone, which also has a video screen, the medical person hangs up on him when she sees the mark.  He is set adrift in this society for his crimes against it, and becomes a pariah; his injuries seemed to be life threatening, but he is left on his own. 

He eventually heals, but as the days go by he becomes more withdrawn.  At the beginning of his sentence he's arrogant and tries to disrupt meetings or parties, but he's singled out by spotlights or by cameras, so he's foiled at every turn.  When he goes into a cafeteria to get something to eat, he just hops over the steam table and piles the food on his plate, while everyone turns away from him.  As the months roll past, he is much more tentative, and when an old man who is blind sits at a table with him, he is astonished.  He can barely speak, after not being talked to for so long.  However, a fellow citizen stops just long enough to whisper a single word, "invisible," to the old blind man, who immediately gets up and runs away, after damning the miscreant. 

The "Invisible" man runs into another "invisible" man, and they both seem shocked.  What is the protocol for two invisible people?  Can they talk to each other?  As they attempt to, one of the flying cameras swoops in and they are warned not to pay attention to each other.  They go on their way.  Finally, his time up, the "invisible" mark is removed and he is welcomed back to his job and his friends.  His friends all say how much he's changed, and become a better person.  He agrees with them, because he does feel as if he's more sympathetic to his fellow man.  One day he stumbles across another "invisible" woman, who begs him to talk to her.  She says that if he had any decency, he would show her that she mattered.  He stops to think a moment, and realizes that she is right.  Decency should extend to all people, no matter what they are.  He hugs her, and tells her she does have worth and he does see her.  The flying cameras roll in, telling him to stop, but he is practicing what this society has taught him.  People matter.