Megillat Esther (the Scroll of Esther) is one of the five megillot (scrolls) in Ketuvim (The last part of the תורה שבכתב, written law). It tells how the Jewish people, living in galut (exile) across the Persian empire after the destruction of the first Beit HaMikdash (Temple), are sentenced to destruction and then saved. It is leined from a scroll on Purim, at night and again in the morning. In cities that were walled in the days of Yehoshua (Joshua), such as Yerushalayim (Jerusalem), it is read on the fifteenth of Adar, Shushan Purim.
King Achashverosh (Ahasuerus) rules 127 provinces from Shushan (Susa). After a great feast he removes Queen Vashti for refusing to appear before him, and Esther, an orphan raised by her cousin (or uncle, or husband, according to different interpretations) Mordechai of Shevet Binyamin, is chosen as the new queen. On Mordechai's instruction she does not reveal that she is Jewish. Mordechai uncovers a plot by two of the king's guards, and his loyalty is written in the royal records.
The king raises Haman the Agagi above all his ministers. Mordechai will not bow to him, and Haman decides to destroy every Jew in the kingdom. He casts a pur (lot) to choose the day, the thirteenth of Adar, and the king signs the decree. Mordechai and the Jews of every province mourn and fast. Mordechai tells Esther that she must go to the king, and after three days of fasting she enters his court without being called.
Esther invites the king and Haman to two feasts. Between them the king cannot sleep, hears how Mordechai saved his life, and has Haman lead Mordechai through the city in royal honor. At the second feast Esther tells the king that Haman has sold her people to be killed, and Haman is hanged on the gallows he built for Mordechai. Mordechai takes Haman's place, and a second decree lets the Jews defend themselves. On the thirteenth of Adar the Jews defeat their enemies, and on the following day they rest and celebrate.
Mordechai and Esther establish the days of Purim for every generation: hearing the megillah, a festive meal, sending food to friends, and giving charity to the poor. Hashem's name does not appear anywhere in the megillah, yet the Chachamim (Sages) see His hand in the way every event comes together for the rescue. Megillat Esther has ten perakim. The Megillah is read with a unique cantillation (trop) for Esther that is not used elsewhere.