The story of Esther is set in Susa, the royal residence of the Persian Empire, to the west of the capital Persepolis, during the years when many Jews were returning to Jerusalem from exile in Babylon (Reference: Esther 1-10).
A Jewish orphan among the exiles in Persia, Esther was brought up by her relative Mordecai.
When the Persian King Xerxes (r. 485 - 464BC) divorced his first wife Vastiti for her refusal to be used as a "sex-toy", Esther became the new Persian Queen.
However, Esther concealed her Jewish heritage from both the King and the royal court. And when a plan to exterminate all Jews was announced, Esther became a potential victim. The plot against the Jews was instigated by Haman, the King's leading politician.
By a mixture of charm and cunning, Esther managed to turn the tables - the emenies of the Jewish people were eliminated (Haman was executed) whilst the Jews themselves survived, improving their social standing in the process - Esther's relative Mordecai was promoted to high office, replacing Haman.