On the seventh day, when the king was merry with wine, he commanded Mehuman, Biztha, Harbona, Bigtha and Abagtha, Zethar and Carkas, the seven eunuchs who attended him, to bring Queen Vashti before the king, wearing the royal crown, in order to show the peoples and the officials her beauty; for she was fair to behold. But Queen Vashti refused to come at the king's command conveyed by the eunuchs. At this the king was enraged, and his anger burned within him. (NRSV 1:10-12)
On the seventh day, when the heart of the king was merry with wine, he commanded Mehuman, Biztha, Harbona, Bigtha, and Abagtha, Zethar, and Carcas, the seven chamberlains that served in the presence of Ahasuerus the king, to bring Vashti the queen before the king with the crown royal, to shew the people and the princes her beauty: for she was fair to look on. But the queen Vashti refused to come at the king's commandment by his chamberlains: therefore was the king very wroth, and his anger burned in him. (KJV 1:10-12)
The king tries to show off his first queen, Vashti, as though she were a sex-object. When she refuses, this starts the chain of events that leads to Esther becoming the new queen.