The Earth is being smothered by humanity in the year 1,000,342. There are 8 planetary colonies dotted around the galaxy and all is ruled by Emperor Floro III. Euthanizing the ill and vagrant is normal and Don Jackson 09823 works for the Cleaner Corp, whose job it is to kill people who have outlived their usefulness.
 

One day he is sent to track down and euthanize a homeless man seen wearing a civil servants red tunic. But when he finds him he recognises his own father, who disappeared 6 years earlier. Saving him would mean death for him as well as for his father, so he decides to set off to the Imperial Palace, to plead for clemency.