After Esther has been made queen and Mordecai has saved the king's life, the king promotes a dude named Haman to be his new head counselor, showering him with honors above all the other officials and ordering everyone to bow down to Haman when he passes by.
However, one man refuses to bow down: Mordecai. People try to convince him, but he says that, since he's a Jew, he can't do it.
Haman is outraged by this act of perceived disrespect. He decides that killing Mordecai alone wouldn't be enough. He needs to kill Mordecai's entire people.
Death by Decree
Haman goes to King Ahasuerus and proposes his plan. He says that there is a people living in the kingdom who have different customs and laws, who won't follow the Empire's own rules.
Thus, Haman argues, it would be appropriate to kill all of them and plunder their wealth for profit.
The king thinks this genocidal plot is a pretty swell plan. He gives Haman his own signet ring and authorizes him to use royal funds to carry out the act.
Haman sends out letters to all the provinces, written in the king's name and sealed with the king's ring. He instructs the different satraps and governors to kill every single Jew—man, woman, and child—on a specific day of the twelfth month of the year.
The couriers go out to issue the decree—which apparently causes all kinds of confusion in the royal capital of Susa—while Haman and the king sit down to enjoy a drink.